Using widget mode Intent=start_call query param does not mute A/V

### Steps to reproduce

1. Where are you starting? What can you see?
where iframe has "..intent=start_call" - not skip lobby, not muted A/V
where iframe has "..intent=start_call&skipLobby=true" - skip lobby OK, not muted A/V
2. What do you click?
Using widgit mode embedding the iframe

### Outcome

#### What did you expect?
"..intent=start_call" is enough to skip lobby since skipLobby is deprecated https://github.com/element-hq/element-call/blob/livekit/docs/url_params.md#common-parameters
- A/V muted should work in widget mode
#### What happened instead?
"..intent=start_call" query param does nothing - no skip lobby, no mute by default

See https://github.com/element-hq/element-call/blob/livekit/docs/url_params.md#common-parameters

Either skipLobby section is written incorrectly (saying that if intent=start_call (default), skipLobby=true), or intent part is written wrong. Because I am using widget mode, I don't use intent query param , the default UI has the lobby, not muted A/V.

I tried "skipLobby=true", this works to skip Lobby, but it does not mute A/V.

### Operating system

Ubuntu

### Browser information

Version 150.0.7871.114 (Official Build) (32-bit)

### URL for webapp

npm package @element-hq/element-call-embedded@0.21.0

### Will you send logs?

No

Start by reading docs/url_params.md and reproducing the report with @element-hq/element-call-embedded@0.21.0 in widget mode. Trace how intent=start_call and skipLobby are handled, then verify whether the documented behavior matches the result: the lobby should be skipped and A/V muted by default, or the documentation should accurately state the behavior.

Written by the indexing model from the issue text.