[Bug]: audio via video call

### What Monal Release channel are you using? AppStore ### iOS system version (if applicable) 26.4 ### macOS system version (if applicable) _No response_ ### Monal version 6.4.19 ### Used XMPP server (domain) chat.example.org ### Which XMPP-Server software are you using? Prosody ### XMPP Server Software Version _No response_ ### How many accounts are you using in Monal? 2 ### What happened? Issue report: Monal version 6.4.19 (1085), test models: Client 1 is "iPhone 7 Plus (iOS 15.8.7)" and Client 2 is "iPhone 14 Pro Max (iOS 26.4)". Bug Description: When an iPhone 7 Plus makes a video call to an iPhone 14 Pro Max, the video call connects successfully, but the iPhone 14 Pro Max hears the other party's audio coming from the microphone (located at the top of the iPhone screen), not the speakerphone, even if the speakerphone icon (hands-free icon) is selected in the video call interface on the iPhone 14 Pro Max. To resolve this, tap the speakerphone icon (hands-free icon) to deselect speakerphone playback, then reselect it. Conversely, when an iPhone 14 Pro Max makes a video call to an iPhone 7 Plus, the iPhone 14 Pro Max's audio defaults to playing normally from the speakerphone. Please test with the same device to ensure this issue is present. ### Anything else? _No response_ ### FAQ - [x] I have [checked the FAQ](https://github.com/monal-im/Monal/wiki/FAQ---Frequently-Asked-Questions) for my issue ### Considerations for XMPP users - [x] I have checked if my issue can be solved with [Considerations for XMPP users](https://github.com/monal-im/Monal/wiki/Considerations-for-XMPP-users) and [Considerations for XMPP server admins](https://github.com/monal-im/Monal/wiki/Considerations-for-XMPP-server-admins) ### XEP-Check - [x] I have checked that at least XEP-198, XEP-0280, XEP-0352, XEP-0357, XEP-0313 and XEP-0163 are activated on my server and shown as 'green' under Settings --> Account--> (i) in advanced settings ### Notifications-Menu - [x] I have checked that all checkmarks are present under Settings --> Notifications