Create dckr-src file path only when neccessary

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

roles/matrix-bot-maubot/tasks/setup_install.yml

@@ -10,7 +10,7 @@
   with_items:
     - {path: "{{ matrix_bot_maubot_base_path }}", when: true}
     - {path: "{{ matrix_bot_maubot_data_path }}", when: true}
-    - {path: "{{ matrix_bot_maubot_docker_src_files_path }}", when: true}
+    - {path: "{{ matrix_bot_maubot_docker_src_files_path }}", when: "{{ matrix_bot_maubot_container_image_self_build }}"}
   when: "item.when|bool"
 
 - name: Ensure maubot configuration file created