Diagnosing when Launcher is in invalid state

Due to bugs, Launcher may end up showing incorrectly, i.e. Launcher app
is present, but no workspace, all apps etc is visible.
Improving diagnostics when this is the case.

Bug: 187761685
Test: presubmit
Flag: N/A
Change-Id: Ibd0228bd26d2ba9ad710895ed8d2e5ece294db21