[branch-bender] Fix verify logic to allow retries

[jovnc]

Exercise Review

Exercise Discussion

Fixes #216

Checklist

• If you require a new remote repository on the Git-Mastery organization, have you created a request for it?
• Have you written unit tests using repo-smith to validate the exercise grading scheme?
• Have you tested your changes using the instructions posted?
• Have you verified that this exercise does not already exist or is not currently in review?
• Did you introduce a new grading mechanism that should belong to git-autograder?
• Did you introduce a new dependency that should belong to app?

[VikramGoyal23]

LGTM!