Picker:Clearable Themes

Build 4127 on andrew/cub-4723-uikit-consumer-api-gaps
Reviewing disabled
Baseline History
Build 412768a4b34
Current build. There are unaccepted changes, so build 4086 is still the baseline.
Build 38700674846
Accepted by Andrey Yamanov.
Build 363426210ae
Accepted by Andrey Yamanov.
Build 3591127553a
Accepted by Andrey Yamanov.
Commenting is disabled because there's a newer build on this branch