Make discarding multiple runs more flexible

The current way to discard multiple runs at once is not flexible enough - let’s say, that some changed triggered 10 stacks/runs, but we want only 2 runs to be executed. Hence, we want to discard 8 specific runs - right now we need to open each run in the new card and discard them one by one. It would be great to have some way to discard multiple (but not all) runs triggered by the same commit.

For example: in the “Runs” dashboard I click on some commit (“Commits” row) or just filter it, and a tickbox to the left of stack’s name would appear - and we could discard selected runs.