♻️(helm) change default customization CM mount path

The mount path used in the backend deployment to mount the customization
file ConfigMap is not the same from the default settings. To avoid extra
configuration we change it to refrlect the default value of
settings.THEME_CUSTOMIZATION_FILE_PATH

Author: lunika

src/helm/impress/values.yaml

@@ -317,7 +317,7 @@ backend:
   themeCustomization:
     enabled: false
     file_content: ""
-    mount_path: /app/configuration/theme/
+    mount_path: /app/impress/configuration/theme
 
 
   ## @param backend.celery.replicas Amount of celery replicas