Environment variable override name is not updated after origin env's name is changed

**Reproduction steps:**

1. Open app's environment variables
2. Create variable and make override for it
3. Change variable's name

Expected result: Variable's override should update it's name to be the same as origin
Actual result: Override keeps previous value and since user is unable to change it from UI the only option is to copy the value and recreate all dependent overrides.

Start by locating the app's environment-variable and override handling, then reproduce the issue by renaming an origin variable with an existing override. Trace where the override name is retained after the origin change. Done means dependent overrides automatically use the origin variable's new name and the reproduction no longer leaves stale names.

Written by the indexing model from the issue text.