Enhance Action Variables to be a dropdown from which the user can select a value

**Why is this needed**: The table actions are a very nice feature and useful. Currently the Action Variables only have an option to accept free text as a string. If I have a large table and want to apply the Action on multiple rows with same input variable, then the user needs to enter the value for each row which sometime becomes tedious. <img width="706" height="147" alt="Image" src="https://github.com/user-attachments/assets/883a1f2d-6529-4dea-9142-415c82262c4a" /> **What would you like to be added**: It would be nice to have dropdown as an option such that I can have my users select a value from the dropdown. This would also help if I wanted to have a limited set of values pre-defined for the variables to select from. (Or maybe take those values from a dashboard variable)