Describe the bug

The disconnected callback in tbs.c does not handle anything related to GTBS: https://github.com/zephyrproject-rtos/zephyr/blob/main/subsys/bluetooth/audio/tbs.c#L352-L378

GTBS, like any TBS instance, should have its pending notifications cleared on disconnect.

Regression

• This is a regression.

Steps to reproduce

N/A

Relevant log output

N/A

Impact

Functional Limitation – Some features not working as expected, but system usable.

Environment

28e25ea

Additional Context

No response