Falls outgoing call

**Describe the bug**
The call uses the matrix-appservice-voip bridge.
A call from the Element to the SIP phone - the Element falls. The call from the phone's SIP to the Element works correctly.
When receiving a call, the application crashes. Element version 1.2.1 and higher.

**To Reproduce**
Unknown.
**Expected behavior**
A connection should be established between the Element and the SIP telephone in both directions of the call. It works correctly on Android versions.

**Screenshots**
The first video with the fall. https://drive.google.com/file/d/12oqyHE8hbwcEErZVLnNl-loM1qhwI9Y8/view?usp=sharing
Second video with a callback. https://drive.google.com/file/d/12pLvw3oamb3D7POGLhsl94YZYnzXgAR9/view?usp=sharing

**Smartphone (please complete the following information):**
- Device: Iphone CE, Iphone 8
- OS: 14.4.2
- Version: 1.2.1 and higher.

Start by reviewing the issue's reproduction details and testing an outgoing call through the matrix-appservice-voip bridge on the listed iPhone and iOS versions. The reproduction steps are marked unknown, so first establish whether the Element app crashes or the call fails, then identify the relevant call-handling entry point and add coverage for successful calls in both directions.

Written by the indexing model from the issue text.