[BUG] Bot creating duplicate "branch created" comments

[idahogurl]

See idahogurl/vs-code-prettier-eslint#36 (comment)

Since it's a hyperlink anyone can click even after the issue is closed or the branch is already created. It shouldn't be creating the branch again or making a new comment. Proposed fix:

• If the issue is closed then it shouldn't do anything. Can't think of a use case where you'd be wanting a branch for a closed issue.. Should update the documentation saying branch will not be created on Closed issues.

• If the comment already exists don't create a new comment or a new branch.