[Feature Request]: Enable Variables in Filter Rows

### What would you like to happen?

I have regular expressions for recurring checks: I would like to use these in filter rows using variables.

Would that be possible?

Thank you very much!

### Issue Priority

Priority: 3

### Issue Component

Component: Transforms

No file or test is named. Start by locating the Transforms component's filter-row implementation and its existing variable handling, then verify the expected behavior for using regular-expression variables in filter rows with focused tests.

Written by the indexing model from the issue text.