Fix comment-triggered profiling SHA reports

[willGraham01]

Builds on #1236 by addressing the following issues:

• Will close Conditionally run set-variables job in run-profiling.yaml workflow file #1123 by adding the if condition to prevent the variables being setup, only to then cancel the workflow later.
• Will close Comment-triggered profiling reports incorrect SHA on pull requests #1300 by correcting the logic used when reporting the commit SHA that the profiling workflow ran on.

[matt-graham]

Looks all good to me, thanks @willGraham01 !