### What problem does this PR solve?
Feat: The key for the begin operator can only contain alphanumeric
characters and underscores. #10427
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Globally defined conversation variables can be selected in the
operator's query variables. #10427
### Type of change
- [x] New Feature (non-breaking change which adds functionality)