Add key storage toggle to Encryption settings (#29310)

* Add key storage toggle to Encryption settings

* Keys in the acceptable order

* Fix some tests

* Fix import

* Fix toast showing condition

* Fix import order

* Fix playwright tests

* Fix bits lost in merge

* Add key storage delete confirm screen

* Fix hardcoded Element string

* Fix type imports

* Fix tests

* Tests for key storage delete panel

* Fix test

* Type import

* Test for the view model

* Fix type import

* Actually fix type imports

* Test updating

* Add playwright test & clarify slightly confusing comment

* Show the advnced section whatever the state of key storage

* Update screenshots

* Copy css to its own file

* Add missing doc & merge loading states

* Add tsdoc & loading alt text to spinner

* Turn comments into proper tsdoc

* Switch to TypedEventEmitter and remove unnecessary loading state

* Add screenshot

* Use higher level interface

* Merge the two hooks in EncryptionUserSettingsTab

* Remove unused import

* Don't check key backup enabled state separately

as we don't need it for all the screens

* Update snapshot

* Use fixed recovery key function

* Amalgamate duplicated CSS files

* Have "key storage disabled" as a separate state

* Update snapshot

* Fix... bad merge?

* Add backup enabled mock to more tests

* More snapshots

* Use defer util

* Update to use EncryptionCardButtons

* Update snapshots

* Use EncryptionCardEmphasisedContent

* Update snapshots

* Update snapshot

* Try screenshot from CI playwright

* Try playwright screenshots again

* More screenshots

* Rename to match files

* Test that 4S secrets are deleted

* Make description clearer

* Fix typo & move related states together

* Add comment

* More comments

* Fix hook docs

* restoreAllMocks

* Update snapshot

because pulling in upstream has caused IDs to shift

* Switch icon

as apparenty the error icon has changed

* Update snapshot

* Missing copyright

* Re-order states

and also sort out indenting

* Remove phantom space

* Clarify 'button'

* Clarify docs more

* Explain thinking behind updating

* Switch to getActiveBackupVersion

which checks that key backup is happining on this device, which is
consistent with EX.

* Add use of Key Storage Panel

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

* Change key storage panel to be consistent

ie. using getActiveBackupVersion(), and add comment

* Add tsdoc

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

* Use BACKUP_DISABLED_ACCOUNT_DATA_KEY in more places

* Expand doc

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

* Undo random yarn lock change

* Use aggregate method for disabling key storage

in https://github.com/matrix-org/matrix-js-sdk/pull/4742

* Fix tests

* Use key backup status event to update

* Comment formatting

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

* Fix comment & put check inside if statement

* Add comment

* Prettier

* Fix comment

* Update snapshot

Which has gained nowrap due to 917d53a56f

---------

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

playwright/e2e/settings/encryption-user-tab/encryption-tab.spec.ts

@@ -17,9 +17,7 @@ import {
 } from "../../crypto/utils";
 
 test.describe("Encryption tab", () => {
-    test.use({
-        displayName: "Alice",
-    });
+    test.use({ displayName: "Alice" });
 
     let recoveryKey: GeneratedSecretStorageKey;
     let expectedBackupVersion: string;
@@ -111,4 +109,36 @@ test.describe("Encryption tab", () => {
         // The user is prompted to reset their identity
         await expect(dialog.getByText("Forgot your recovery key? You’ll need to reset your identity.")).toBeVisible();
     });
+
+    test("should warn before turning off key storage", { tag: "@screenshot" }, async ({ page, app, util }) => {
+        await verifySession(app, recoveryKey.encodedPrivateKey);
+        await util.openEncryptionTab();
+
+        await page.getByRole("checkbox", { name: "Allow key storage" }).click();
+
+        await expect(
+            page.getByRole("heading", { name: "Are you sure you want to turn off key storage and delete it?" }),
+        ).toBeVisible();
+
+        await expect(util.getEncryptionTabContent()).toMatchScreenshot("delete-key-storage-confirm.png");
+
+        const deleteRequestPromises = [
+            page.waitForRequest((req) => req.url().endsWith("/account_data/m.cross_signing.master")),
+            page.waitForRequest((req) => req.url().endsWith("/account_data/m.cross_signing.self_signing")),
+            page.waitForRequest((req) => req.url().endsWith("/account_data/m.cross_signing.user_signing")),
+            page.waitForRequest((req) => req.url().endsWith("/account_data/m.megolm_backup.v1")),
+            page.waitForRequest((req) => req.url().endsWith("/account_data/m.secret_storage.default_key")),
+            page.waitForRequest((req) => req.url().includes("/account_data/m.secret_storage.key.")),
+        ];
+
+        await page.getByRole("button", { name: "Delete key storage" }).click();
+
+        await expect(page.getByRole("checkbox", { name: "Allow key storage" })).not.toBeChecked();
+
+        for (const prom of deleteRequestPromises) {
+            const request = await prom;
+            expect(request.method()).toBe("PUT");
+            expect(request.postData()).toBe(JSON.stringify({}));
+        }
+    });
 });