Prevent crashes on Wear when offline / server no longer available

[jpelgrom]

Summary

While helping a user with problems in their Wear app, it became clear that the app provides almost no options to do anything and is easy to crash if the server can't be reached. This PR aims to address that.

• Catch exceptions thrown when executing calls to change an entity state instead of crashing the app. No visual feedback is provided as the app always shows the live state, so the lack of a visible change should be enough to indicate failure.
• Allow opening Settings when loading entities failed to make it possible to sign out.
• When logging out from the app fails during revokeSession, instead of crashing catch it and continue with logout in the app as the server might no longer be available. This better matches the options available when the main app can't reach the server.

Without the last two changes, if the server is no longer available the user might be 'locked in' with no way to change the server aside from resetting the entire app.

Screenshots

The main screen now shows the settings button below the 'Error loading entities' message:

Link to pull request in Documentation repository

n/a

Any other notes