Add support for device dehydration v2 (#12316)

* rehydrate/dehydrate device if configured in well-known

* add handling for dehydrated devices

* some fixes

* schedule dehydration

* improve display of own dehydrated device

* created dehydrated device when creating or resetting SSSS

* some UI tweaks

* reorder strings

* lint

* remove statement for testing

* add playwright test

* lint and fix broken test

* update to new dehydration API

* some fixes from review

* try to fix test error

* remove unneeded debug line

* apply changes from review

* add Jest tests

* fix typo

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

* don't need Object.assign

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

---------

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

test/test-utils/test-utils.ts

@@ -115,6 +115,8 @@ export function createTestClient(): MatrixClient {
         credentials: { userId: "@userId:matrix.org" },
         bootstrapCrossSigning: jest.fn(),
         hasSecretStorageKey: jest.fn(),
+        getKeyBackupVersion: jest.fn(),
+        checkOwnCrossSigningTrust: jest.fn(),
 
         secretStorage: {
             get: jest.fn(),