Fix merging of `_auto` and `_custom` into `matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci` so that a list is produced

`group_vars/matrix_servers` was correctly populating `matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_auto` with a list, but:

- the defaults for these variables were hinting that hashmaps are necessary

- merging of `_auto` and `_custom` was done as if for hashmaps, not lists

As a result, `/.well-known/matrix/client` looked like this:

```json
{
	"org.matrix.msc4143.rtc_foci": {
		"livekit_service_url": "https://matrix.example.com/livekit-jwt-service",
		"type": "livekit"
	}
}
```

.. instead of what's expected as per MSC4143 (https://github.com/matrix-org/matrix-spec-proposals/pull/4143):

```json
{
	"org.matrix.msc4143.rtc_foci": [
		{
			"livekit_service_url": "https://matrix.example.com/livekit-jwt-service",
			"type": "livekit"
		}
	]
}
```

Regardless of our incorrectly formatted `org.matrix.msc4143.rtc_foci`
configuration in `/.well-known/matrix/client`, Element Web still seemed
to be able to discover LiveKit JWT Service (and by extension, LiveKit Server) correctly,
even without this fix.

roles/custom/matrix-static-files/defaults/main.yml

@@ -218,9 +218,9 @@ matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_enab
 
 # Controls the org.matrix.msc4143.rtc_foci property in the /.well-known/matrix/client file.
 # See `matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_enabled`
-matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci: "{{ matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_auto | combine(matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_custom, recursive=True) }}"
-matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_auto: {}
-matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_custom: {}
+matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci: "{{ matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_auto+ matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_custom }}"
+matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_auto: []
+matrix_static_files_file_matrix_client_property_org_matrix_msc4143_rtc_foci_custom: []
 
 # Default /.well-known/matrix/client configuration template which covers the generic use case.
 # You can customize it by controlling the various variables inside it.