BassClientService: fix binder logic

mainly 2 things:
1/ Catching "exception because it happens" should be avoided, this
prevent throwing securityexception and other valid exception such as
InvalidArgument or an expected NullPointer check

2/ calling clearInvocation on mockito is not recommended and here it can
be easily avoided by splitting the tests

Change-Id: Ic26bfd24facc303eb77c8c374a9bfd81293b76b8
Bug: 349682934
Bug: 350563786
Test: atest BluetoothInstrumentationTests
Flag: Exempt as impacting mainly and required change to enforce
      permissions properly (b/349682934)