Bug 937336 - Remove where possible explicit frame switching

Replacing explicit frame switching calls to use the encapsulated switch_to_displayed_app method
Bug 952455 - [Contacts][Bluetooth] "Export to Bluetooth" message blocks the Contacts app and leaves it unusable
Merge pull request #14849 from bobsilverberg/switch_to_displayed_app

Bug 937336 - Remove where possible explicit frame switching
Merge pull request #14897 from gtorodelvalle/contacts-bug-952455-export-to-bluetooth

Bug 952455 - [Contacts][Bluetooth] "Export to Bluetooth" message blocks the Contacts app and leaves it unusable