Do not hardcode https:// in all remaining places, refer to matrix_static_files_scheme

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3333

roles/custom/matrix-client-hydrogen/defaults/main.yml

@@ -124,6 +124,8 @@ matrix_client_hydrogen_floc_optout_enabled: true
 # See: `matrix_client_hydrogen_http_header_strict_transport_security`
 matrix_client_hydrogen_hsts_preload_enabled: false
 
+matrix_client_hydrogen_scheme: https
+
 # The hostname at which Hydrogen is served.
 matrix_client_hydrogen_hostname: "{{ matrix_server_fqn_hydrogen }}"