Remove Jinja2 templating delimiters from when statement

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/1629

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1505

roles/matrix-bridge-hookshot/tasks/setup_install.yml

@@ -69,7 +69,7 @@
     mode: 0400
     owner: "{{ matrix_user_username }}"
     group: "{{ matrix_user_groupname }}"
-  when: "{{ matrix_hookshot_github_enabled|bool and matrix_hookshot_github_private_key|length }}"
+  when: matrix_hookshot_github_enabled|bool and matrix_hookshot_github_private_key|length > 0
 
 - name: Ensure matrix-hookshot.service installed
   template: