When retrieving an unset shortcut value, the error is not silenced but instead we use the null-coalesce operator to define a default value.

See #7290

Closes #7290

Changes proposed in this pull request:

• default values are set instead of silencing errors.

How to test the feature manually:

1. Validate that empty shortcuts are configured properly in the interface.
2. Validate that defined shortcuts are configured properly in the interface.

Pull request checklist:

• clear commit messages
• code manually tested
• unit tests written (optional if too hard)
• documentation updated

Additional information can be found in the documentation.