Now that https://github.com/element-hq/element-web/pull/29471
is part of v1.11.96, we don't need to carry around this custom workaround.

This also reverts e5574a405e because:
- it was causing issues on some servers (not clear why)
- such workarounds are no longer necessary when doing multi-stage building.

"briges" -> "bridges"

This is a security patch for Synapse that fixes an actively exploited bug.

Fix missing "reverse_proxy" argument line 35

Related to:

- d96ce10d57
- https://github.com/mother-of-all-self-hosting/ansible-role-traefik/pull/6
- https://github.com/mother-of-all-self-hosting/ansible-role-traefik/issues/5

Various old guides mention this, but it seems like neither Element Web,
nor Element Desktop make use of it.

Element Web & Element Desktop use their own `config.json` configuration to figure out where
Element Call is.

Some Element Call setup resources say that `/.well-known/element/element.json` should be served on the base domain
and should contain content like this:

```json
{
	"call": {
		"widget_url": "https://call.element.example.com"
	}
}
```

We were already generating the file via `matrix-static-files`, but weren't serving it yet.

This patch makes sure it's served on the `matrix.` domain, which allows
people to set up serving on the base domain via a redirect or reverse-proxying.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3562