Fix missing job action button in CI report 
# What does this PR do?

Current CI reports lack the `GitHub Action Job` button, due to the recent changes in workflow files:
 - `models/bert` -> `models_bert` (was done in artifact names, but not in the matrix)
 - `[single|multi]-gpu-docker` -> `[single|multi]-gpu` (was done in `notification_service.py`, but not in scheduled CI workflow)

This PR fixes the issues by:
- Let the workflow files use `single-gpu` and `multi-gpu` as matrix and artifact names. Only adds `-docker` in `runs-on:` for scheduled CI.
- Add `model.replace('models_', 'models/'`) at a proper place in `notification_service.py`
_The documentation is not available anymore as the PR was closed or merged._