leaudio: Fix double iso data path removal

When phone call ends and Sink ASE and Sink Source goes to Releasing
state, Host will remove data path. This patch makes sure it is sent only
once.

Bug: 290801282
Test: atest --host bluetooth_le_audio_test
Test: atest BluetoothInstrumentationTests
Tag: #feature
Change-Id: If261faea30a19c425ca0dea6932e5c889c6132a0