Alert tone PTT timeout causes a dekey regardless of whether PTT is held

**Describe the bug**
When using an alert tone, the 5 second PTT timeout drops the call regardless of whether or not PTT remains held.

**To Reproduce**
Steps to reproduce the behavior:
1. Start a transmission
2. Send an alert tone
3. Hold PTT
4. The call will drop after the 5 second timeout

**Expected behavior**
If PTT is held, the call should not drop
