Fix workflow injection on issue open

[AdnaneKhan]

Simple fix here, the issue body is under control of other users and can be used to inject arbitrary code.

Opening a PR instead of privately reporting since this is not an official GitHub repo for the BB program.

Reference:

• https://www.praetorian.com/blog/pwn-request-hacking-microsoft-github-repositories-and-more/

[LadyKerr]

thank you for your contribution!