Make Element Call fail during validation if on an unsupported architecture (like arm32)

roles/custom/matrix-element-call/defaults/main.yml

@@ -20,6 +20,10 @@ matrix_element_call_path_prefix: /
 
 matrix_element_call_base_path: "{{ matrix_base_data_path }}/element-call"
 
+# The architecture for Element Call container images.
+# Recognized values by us are 'amd64', 'arm32' and 'arm64'.
+matrix_element_call_architecture: "{{ matrix_architecture }}"
+
 matrix_element_call_container_image: "{{ matrix_element_call_container_image_registry_prefix }}element-hq/element-call:{{ matrix_element_call_container_image_tag }}"
 matrix_element_call_container_image_registry_prefix: "{{ matrix_element_call_container_image_registry_prefix_upstream }}"
 matrix_element_call_container_image_registry_prefix_upstream: "{{ matrix_element_call_container_image_registry_prefix_upstream_default }}"

roles/custom/matrix-element-call/tasks/validate_config.yml

@@ -6,6 +6,13 @@
 
 ---
 
+- name: Fail if Element Call architecture is not supported
+  ansible.builtin.fail:
+    msg: >
+      Element Call is only supported on amd64 and arm64 architectures.
+      Your architecture is configured as '{{ matrix_element_call_architecture }}'.
+  when: "matrix_element_call_architecture not in ['amd64', 'arm64']"
+
 - name: Fail if required Element Call settings are not defined
   ansible.builtin.fail:
     msg: >