Log exceptions in AppFunctionService

This change adds logs in AppFunctionService in case that a client app doesn't handle exceptions correctly. this makes debugging easier.

If they do call the onError callback, which means the devs have handled the exception. In that case, whether to log it is up to them.

Flag: EXEMPT add a simple log
Bug: 413302149

Change-Id: I67b52c1092bc622c723afb3dadec4eaefeb66f35