Error could come earlier for misconfigured GPG key that incorrectly possesses a passphrase

[rtyley]

If the user provides a GPG key that, against requirements, is not passphrase-less, the flow will fail on the 3rd job (🔒 Push Release Commit) - but we could do a quick check in step 1 (🔒 Read Signing Key Id) and give faster feedback.

Sample failed workflow run that shows an error that could have come sooner

https://github.com/rtyley/sample-project-using-gha-scala-library-release-workflow/actions/runs/7328509323/job/19956907992

error: gpg failed to sign the data:
[GNUPG:] KEY_CONSIDERED 838880CDFC6A969658E402D6E93376570A5421BF 2
[GNUPG:] BEGIN_SIGNING H8
[GNUPG:] PINENTRY_LAUNCHED 1812 curses 1.1.1 - - - - 1001/127 -
gpg: signing failed: Inappropriate ioctl for device
[GNUPG:] FAILURE sign 839189[50](https://github.com/rtyley/sample-project-using-gha-scala-library-release-workflow/actions/runs/7328509323/job/19956907992#step:5:51)
gpg: signing failed: Inappropriate ioctl for device

error: failed to write commit object
fatal: cherry-pick failed
Error: Process completed with exit code 128.