Add case DisconnectCause.NORMAL_UNSPECIFIED to play tone ToneGenerator.TONE_PROP_PROMPT

If hang up call from the remote side, the disconnect cause maybe DisconnectCause.NORMAL_UNSPECIFIED.
It needs to consider this disconnect cause to play call end tone.

Bug: 77499488
Test: Manual testing
Change-Id: I2c9eaa8fe01ee2e62b91225d92aebec01ab453ae
1 file changed