Uses phone speaker if headphone without mic is inserted

### Steps to reproduce

Started at a room with only two persons (including myself).

I start a video call by clicking the video icon, when a headphone without mic is inserted.

### Outcome

#### What did you expect?
I would expect that Element would output voice through the headphone, and receive input voice from phones mic, just as the phone app does.

#### What happened instead?
Element uses phone speaker instead of the headphone.

### Your phone model

Xiaomi Redmi Note 7

### Operating system version

Android 10.0

### Application version and app store

Element version 1.5.30 [40105300] (F-0b09a51b), olm 3.2.12 from F-Droid

### Homeserver

matrix.org

### Will you send logs?

Yes

### Are you willing to provide a PR?

Yes