Updating an application variable in Workspace / Applications / <App> /
Settings persisted server-side but the Apollo cache kept the old value.
Switching tabs unmounted the settings tab, and remounting reseeded the
input from the stale cache — only a full refresh showed the new value.
Mutation now writes the new value into the ApplicationVariable entity
via cache.modify, so FindOneApplication reflects the change immediately.
Hook + table updated to pass the variable id through.
Adds a hook test that pre-seeds the cache and asserts the cached value
after the mutation.
NOTE: saving the plain value in Apollo's cache might not be the best
approach here
---------
Co-authored-by: martmull <martmull@hotmail.fr>
