AAudio AudioStreamLegacy: refine handling of AudioTrack teardown

Do not systematically request a stream disconnect upon
EVENT_NEW_IAUDIOTRACK received AudioTrack but only if the new
audio Track properties have changed in such a way that the initial
contract is broken.

Bug: 139763500
Test: OboeTester TEST DISCONNECT
Test: OboeTester TEST OUTPUT while enabling/disabling Live Caption
Change-Id: I3b43275a888e23471fcd1ce20725f5731a77a255