Compatibility check does not point out source of incompatibility in case of missing/disabled webaudio API

### Steps to reproduce

1. I'm starting with a Firefox-based browser with no webpages open. It's `dom.webaudio.enabled` about:config settings has happened to be false
2. I have navigated to https://app.element.io/
3. The webapp tells there is a compatibility issue with my browser, but does not tell what is that
4. I click the "Continue anyway" button
5. The webapp shows the unsupported browser page, but does not tell why is that

### Outcome

#### What did you expect?
A short (or longer, when more information would be useful) description that Element could not access the browser's WebAudio API. An error message you got could also be useful to be displayed for the generic case.

#### What happened instead?
The webapp did not tell the reason of incompatibility.

#### Additional information

According to #27864, you have already implemented such a feature, but it seems there may be something preventing it from working.
I have mentioned the issue there earlier, but did not get a response about whether this is expected or unexpected behavior, so I have opened this issue in the belief that this is unexpected behavior.

I expect that the incompatibility in this case is the missing WebAudio API, because if I enable it in about:config the webapp will load fine.

### Operating system

Windows

### Browser information

Firefox

### URL for webapp

https://app.element.io/

### Application version

_No response_

### Homeserver

_No response_

### Will you send logs?

No