Copy HotwordDetectionConnection into TrustedHotwordDetectorSession

The HotwordDetectionConnection controls the communication
with the HotwordDetectionService and handles the detection
of trusted hotword detector. We separate the detection of
trusted hotword detector into TrustedHotwordDetectorSession.

In order to make the code review easier, we copy the all
content of HotwordDetectionConnection class into the new
TrustedHotwordDetectorSession class.

Test: atest CtsVoiceInteractionTestCases
Bug: 241041976
Change-Id: I0943fdec5979440aaab23642caa5677470002466