Warn users if results will not be retained when merging Test Runs with differing Datasets

Background
Currently, when merging a Test Run that uses a Parameterized Test, the Actual Result field is erased if changes are made to the Dataset (e.g., renaming a parameter). This happens because, after modifying the Dataset, existing Test Runs must be reset, as it is unclear whether the changes affect the meaning of the steps.

Suggestions
When data will be removed, the user should be warned that the action they are about to take will result in the field being reset.