Notify stability calculator on failed text insertion.

When `insertText` fails because no `InputConnection` is found, the `StabilityCalculator` is now immediately notified of an interaction failure, which triggers the stability listener without waiting for a timeout. This ensures that the session is marked as stable even when an expected input connection is missing.

Test: atest ComputerControlSessionTest
Flag: EXEMPT bugfix
Bug: 422134565
Change-Id: I870edd8927df4c2e7411cf8dc9c132b2ef1e6adc