Cannot set min/max bitrate at stream start time from frontend

[DenisTensorWorks]

**UE Version: **
UE 5.2

Problem component
Frontend

Description
Min/MaxBitrate unable to be set from frontend at stream start time, neither it can be configured during stream running.
It does, however, work if the stream is re-started.

Reason being, UE sends its initial settings message which contains the information about min/max bitrate, which overrides what’s set on the frontend before the frontend has a chance to send its URL values.

For context, if the limitations are added to application launch args instead, i.e. -PixelStreamingEncoderMaxBitrate=5000, they work as expected.

Suggested fix is to send this info as a config message.

[mcottontensor]

This is a tricky one since the config would need to be sent before the stream starts but we have no connection to the endpoint until the webrtc connection is negotiated and streaming.
Perhaps there is something we can put in the SDP.

[github-actions]

Issues go stale after 30 days of inactivity. Please comment or re-open the issue if you are still interested in getting this issue fixed.

[lukehb]

I do think when we loop round to this, we should consider putting the metadata into the SDP - that actually seems pretty reasonable considering what we are trying to achieve here.