Clean up doNotSkipImeByTargetVisibility flag

The bugfix flag was enabled over one month.

Bug: 339375944
Flag: EXEMPT remove dead code for launched flag
Test: WindowContainerTraversalTests#testTraverseImeRegardlessOfImeTarget
Change-Id: Ide148322b410c1a84b7d885633f1d2396dbd809a
4 files changed