## Description
GNOME Shell 49.3 crashes and logs out the user when a Bluetooth headset (Bose QC35) automatically switches between A2DP and HSP/HFP audio profiles during application usage (Slack, Google Meet).

Note: The crash does NOT occur with Bluetooth speakers, only with headsets that have microphone capabilities.

The assertion failure occurs when trying to get audio port information during the PulseAudio sink update callback.

## System Information
- OS: Fedora 43
- GNOME Shell: 49.3-1.fc43
- Mutter: 49.2-2.fc43
- PipeWire: 1.4.10-1.fc43
- PulseAudio: 17.0-7.fc43
- WirePlumber: (installed, version from fc43 repos)
- Display Server: Wayland
- Bluetooth Device: Bose QC35 headphones


Reproducible: Always

Steps to Reproduce:
1. Connect Bose QC35 Bluetooth headset
2. Start Slack or Google Meet
3. Join a call or start audio playback
4. When the system automatically switches audio output to the headset, GNOME Shell crashes
Actual Results:
GNOME Shell crashes immediately when the audio profile switches, logging the user out to GDM.

Expected Results:
GNOME Shell should handle Bluetooth profile switching gracefully without crashing.


Additional Information:
Stack trace shows the crash occurs in libgvc.so (GNOME Volume Control):

```
#8  0x00007f82f9f4a727 g_assertion_message_expr (libglib-2.0.so.0 + 0x73727)
#9  0x00007f829403a3c9 gvc_mixer_stream_get_port (libgvc.so + 0xa3c9)
#10 0x00007f829403c820 update_sink (libgvc.so + 0xc820)
#11 0x00007f82701f4c55 context_get_sink_info_callback.lto_priv.0 (libpulse.so.0 + 0xfc55)
```