Refactor the various email/phone management UI into a single component (#12884)

* Refactor the various email/phone management UI into a single component

These were basically the same component copied & pasted 3 times and
tweaked to match the behaviour of each case. This de-dupes them into
one component.

This all could really benefit from playwright tests, but would require
setting up a dummy ID server in the playwright tests. This is all legacy
pre-MAS stuff so its questionable whether its worth the effort.

* Basic test, remove old tests

* Use different text to confirm remove & put headers back

although the two texts are both 'Remove' in practice

* Remove string

This was never triggered anyway with sydent & synapse because they
don't seem to agree on what error to return. In any case, I think it
makes more sense for it to be consistent with the email path, ie. using
a dialog.

* Avoid nested forms

* Snapshots

* More snapshots

* Test the hs side

* Snapshots

* Test IS bind/revoke

* Test remove can be cancelled

* Test unvalidated cases & fix phone error

* Reset state between tests

* Import useState directly

* One more direct React import

test/test-utils/test-utils.ts

@@ -265,8 +265,13 @@ export function createTestClient(): MatrixClient {
         knockRoom: jest.fn(),
         leave: jest.fn(),
         getVersions: jest.fn().mockResolvedValue({ versions: ["v1.1"] }),
+        requestAdd3pidEmailToken: jest.fn(),
         requestAdd3pidMsisdnToken: jest.fn(),
         submitMsisdnTokenOtherUrl: jest.fn(),
+        deleteThreePid: jest.fn().mockResolvedValue({}),
+        bindThreePid: jest.fn().mockResolvedValue({}),
+        unbindThreePid: jest.fn().mockResolvedValue({}),
+        requestEmailToken: jest.fn(),
         addThreePidOnly: jest.fn(),
         requestMsisdnToken: jest.fn(),
         submitMsisdnToken: jest.fn(),