catch stopRecognition exceptions in destroy()

Ignore any exceptions coming out of the HotwordDetector#destroy()
method when stopRecognition is called. The stopRecognition call here is
a best effort call which should not be retried if it fails.

Test: atest CtsVoiceInteractionTestCases
Test: atest CtsVoiceInteractionHostTestCases
Bug: 193232191
Change-Id: Ie4f8e68ca9078dca0e30fe73408947a2525c5b9a