matrix_rtc details not included in client well-known

### Description

Setting `public_baseurl` in `homeserver.yaml` allows Synapse to expose the `.well-known/matrix/client` endpoint to generate the needed output automatically. This allows, for example, the needed output to be generated for the Matrix Authentication Service.

It does **not**, however, generate the required output for Matrix RTC from the settings provided. That currently needs to be included manually using the separate `extra_well_known_client_content` setting. This information should be generated and included based on the settings in the `homeserver.yaml`.

And if the configuration does currently include `org.matrix.msc4143.rtc_foci` under `extra_well_known_client_content`, that setting should be ignored in favor of the auto-generated output.

### Steps to reproduce

In the homeserver.yaml:
```
public_baseurl: "https://[homeserver]/

matrix_rtc:
transports:
- type: livekit
livekit_service_url: https://[livekit-hostname]/
```
Run an HTTP request against `https://[homeserver]/.well-known/matrix/client`. Observe the output does not include the `org.matrix.msc4143.rtc_foci` section with the object(s) from `matrix_rtc.transports`.

### Homeserver

Personal homeserver

### Synapse Version

1.147.1

### Installation Method

Docker (matrixdotorg/synapse)

### Database

PostgrSQL, brand new installation, single server for Synapse

### Workers

Single process

### Platform

Docker on a virtual machine. 4 cores. 4GB RAM.

### Configuration

MSCs: 3266, 4108, 4140, 4143, 4222

### Relevant log output

```shell
Not applicable
```

### Anything else that would be useful to know?

_No response_