Allowing Intellij Macros in Run/Debug Configurations dialog.

## Steps to Reproduce

Currently, this flutter plugin does not support macros like `$FilePathRelativeToProjectRoot$` as target `Test file` in Run/Debug Configurations dialog.

Allowing that would enable users to run test files out of the `/test` folder conveniently. For large projects, it's sometimes better to put test file in the same directory with the logic being tested.

## Version info

All versions.