fix(mobile): face thumbnail stuck blank after renaming a person (#30769)
* fix(mobile): face thumbnail stuck blank after renaming a person
* flatten the codec error guard and rework the tests around framework driven reuse
* trim the image provider tests and note the per load state rule
* keep two small image provider tests: the renamed face and a late failure of a cancelled load
* clearer image provider tests: return the created completer, comment the steps, drop the unused listener, rename to thumbWithChecksum
* use the provider constructor with a lint ignore in the cache key test
(cherry picked from commit a29153e90e127ee26ad7555f6fb7c562b97b4abe)
Co-authored-by: Santo Shakil <santoshakil@users.noreply.github.com>
* fix(mobile): decode remote thumbnails at displayed size
* use nullable decode size and reuse the tapped thumbnail in the viewer
* clean up decode size naming and guards
