Make the ThemePicker remember the state before system config changes

1. It was added the logic to save the selection, but it was overrided by active theme. Fix it in the cl.
2. Remove optionsController#setAppliedOption from ThemeFragment, since the #1 get fixed, we will see two thumbnails with check, see: https://drive.google.com/file/d/1bl20BBxCi7lRWnBV-vD4xmvx5MWwGH9i/view?usp=sharing
The thumbnail check would be added by OptionSelectorController, the ThemeFragment won't handle it. (Same as GridFragment)

Video of the fixing: https://drive.google.com/file/d/1dhu1oR0T2gR0ZE-vyFjL5XQTeY3zkvBK/view?usp=sharing

Test: Manually
Fixes: 157723282
Fixes: 157724003
Change-Id: Ib668b7ca0f7630065c6da2df19b276ccca05eb5a