Fix flaky jest tests (#12486)

...and remove the code that causes them to be retried in CI. Most of
these were just lack of waiting for async things to happen, mostly
lazy loading components, hence whythey worked on the retry: because
the code had been loaded by then.

test/setupTests.ts

@@ -37,13 +37,6 @@ beforeEach(() => {
     });
 });
 
-// Retry to work around our flaky app & tests
-if (process.env.CI) {
-    jest.retryTimes(2, {
-        logErrorsBeforeRetry: true,
-    });
-}
-
 // Very carefully enable the mocks for everything else in
 // a specific order. We use this order to ensure we properly
 // establish an application state that actually works.