* 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