Building upon the existing command-level disable auth check logic, this commit adds flag-level disable auth check logic
for any flag set with `-b,--bundle` flag of `gh attestation verify` being the first use case.
Subsequent commit to build out testing is needed as IsAuthCheckEnabled does not have tests.
Those hidden command are used by the shell completion scripts, but they
are not disabled auth check. Thus, the shell completion does not work
even the completion setup was done properly.
Fixes#4188
