Remove `synapse_admin_container_image_registry_prefix_*`

Signed-off-by: Suguru Hirahara <did🔑z6MkvVZk1A3KBApWJXv2Ju4H14ErDfRGxh8zxdXSZ4vACDg5>

roles/custom/matrix-synapse-admin/defaults/main.yml

@@ -30,8 +30,6 @@ synapse_admin_container_image_self_build_repo: "https://github.com/etkecc/synaps
 # renovate: datasource=docker depName=ghcr.io/etkecc/synapse-admin
 synapse_admin_version: v0.11.1-etke53
 synapse_admin_container_image: "{{ synapse_admin_container_image_registry_prefix }}etkecc/synapse-admin:{{ synapse_admin_version }}"
-synapse_admin_container_image_registry_prefix: "{{ 'localhost/' if synapse_admin_container_image_self_build else synapse_admin_container_image_registry_prefix_upstream }}"
-synapse_admin_container_image_registry_prefix_upstream: "{{ synapse_admin_container_image_registry_prefix_upstream_default }}"
 synapse_admin_container_image_registry_prefix_upstream_default: "ghcr.io/"
 synapse_admin_container_image_force_pull: "{{ synapse_admin_container_image.endswith(':latest') }}"