Use Kotlin coroutines for SuggestedDeviceConnectionManager.

The improvements are:
- Scan and connection are 2 sequential suspend functions with a limited
 scope.
- Reduce to a minimum mutable state within the class.
- Having a separate 10 second timeout for scan and 20 second timeout for
 connection.
- Ability to cleanup resources with the `cancel` method.

Bug: 443107229
Bug: 442856281
Test: atest SuggestedDeviceConnectionManagerTest
Test: atest SuggestedDeviceManagerTest
Test: On a physical device
Flag: com.android.media.flags.use_suggested_device_connection_manager
Change-Id: I77b11d64d1125ba55376002615d0fe29949c5f06