Prompt the user when key storage is unexpectedly off (#29912)

* Assert that we set backup_disabled when turning off key storage

* Prompt the user when key storage is unexpectedly off

* Playwright tests for the Turn on key storage toast

test/unit-tests/components/views/dialogs/ConfirmKeyStorageOffDialog-test.tsx

@@ -0,0 +1,40 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import React from "react";
+import { render } from "jest-matrix-react";
+
+import ConfirmKeyStorageOffDialog from "../../../../../src/components/views/dialogs/ConfirmKeyStorageOffDialog";
+
+describe("ConfirmKeyStorageOffDialog", () => {
+    beforeEach(() => {
+        jest.resetAllMocks();
+    });
+
+    it("renders", () => {
+        const dialog = render(<ConfirmKeyStorageOffDialog onFinished={jest.fn()} />);
+        expect(dialog.asFragment()).toMatchSnapshot();
+    });
+
+    it("calls onFinished with dismissed=true if we dismiss", () => {
+        const onFinished = jest.fn();
+        const dialog = render(<ConfirmKeyStorageOffDialog onFinished={onFinished} />);
+
+        dialog.getByRole("button", { name: "Yes, dismiss" }).click();
+
+        expect(onFinished).toHaveBeenCalledWith(true);
+    });
+
+    it("calls onFinished with dismissed=true if we continue", () => {
+        const onFinished = jest.fn();
+        const dialog = render(<ConfirmKeyStorageOffDialog onFinished={onFinished} />);
+
+        dialog.getByRole("button", { name: "Go to Settings" }).click();
+
+        expect(onFinished).toHaveBeenCalledWith(false);
+    });
+});

test/unit-tests/components/views/dialogs/__snapshots__/ConfirmKeyStorageOffDialog-test.tsx.snap

@@ -0,0 +1,82 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`ConfirmKeyStorageOffDialog renders 1`] = `
+<DocumentFragment>
+  <div
+    class="mx_EncryptionCard"
+  >
+    <div
+      class="mx_EncryptionCard_header"
+    >
+      <div
+        class="_content_o77nw_8 _destructive_o77nw_34"
+        data-size="large"
+      >
+        <svg
+          fill="currentColor"
+          height="1em"
+          viewBox="0 0 24 24"
+          width="1em"
+          xmlns="http://www.w3.org/2000/svg"
+        >
+          <path
+            d="M12 17q.424 0 .713-.288A.97.97 0 0 0 13 16a.97.97 0 0 0-.287-.713A.97.97 0 0 0 12 15a.97.97 0 0 0-.713.287A.97.97 0 0 0 11 16q0 .424.287.712.288.288.713.288m0-4q.424 0 .713-.287A.97.97 0 0 0 13 12V8a.97.97 0 0 0-.287-.713A.97.97 0 0 0 12 7a.97.97 0 0 0-.713.287A.97.97 0 0 0 11 8v4q0 .424.287.713.288.287.713.287m0 9a9.7 9.7 0 0 1-3.9-.788 10.1 10.1 0 0 1-3.175-2.137q-1.35-1.35-2.137-3.175A9.7 9.7 0 0 1 2 12q0-2.075.788-3.9a10.1 10.1 0 0 1 2.137-3.175q1.35-1.35 3.175-2.137A9.7 9.7 0 0 1 12 2q2.075 0 3.9.788a10.1 10.1 0 0 1 3.175 2.137q1.35 1.35 2.137 3.175A9.7 9.7 0 0 1 22 12a9.7 9.7 0 0 1-.788 3.9 10.1 10.1 0 0 1-2.137 3.175q-1.35 1.35-3.175 2.137A9.7 9.7 0 0 1 12 22m0-2q3.35 0 5.675-2.325T20 12t-2.325-5.675T12 4 6.325 6.325 4 12t2.325 5.675T12 20"
+          />
+        </svg>
+      </div>
+      <h2
+        class="_typography_6v6n8_153 _font-heading-sm-semibold_6v6n8_93"
+      >
+        Are you sure you want to keep key storage turned off?
+      </h2>
+    </div>
+    <span>
+      If you sign out of all your devices you will lose your message history and will need to verify all your existing contacts again. 
+      <br />
+      <a
+        href="https://element.io/help#encryption5"
+        rel="noreferrer noopener"
+        target="_blank"
+      >
+        Learn more 
+        <svg
+          fill="currentColor"
+          height="1em"
+          viewBox="0 0 24 24"
+          width="1em"
+          xmlns="http://www.w3.org/2000/svg"
+        >
+          <path
+            d="M5 3h6a1 1 0 1 1 0 2H5v14h14v-6a1 1 0 1 1 2 0v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2"
+          />
+          <path
+            d="M15 3h5a1 1 0 0 1 1 1v5a1 1 0 1 1-2 0V6.414l-6.293 6.293a1 1 0 0 1-1.414-1.414L17.586 5H15a1 1 0 1 1 0-2"
+          />
+        </svg>
+      </a>
+    </span>
+    <div
+      class="mx_EncryptionCard_buttons"
+    >
+      <button
+        class="_button_vczzf_8"
+        data-kind="primary"
+        data-size="lg"
+        role="button"
+        tabindex="0"
+      >
+        Go to Settings
+      </button>
+      <button
+        class="_button_vczzf_8"
+        data-kind="secondary"
+        data-size="lg"
+        role="button"
+        tabindex="0"
+      >
+        Yes, dismiss
+      </button>
+    </div>
+  </div>
+</DocumentFragment>
+`;