use_pam_wheel_group_for_su remediation fails if setting is not present

#### Description of problem:

When `/etc/pam.d/su` does not contain the required setting remediation fails.

Code looks for the presence of `auth required pam_wheel.so use_uid group=.....` and during remediation attempts to un-comment the line if it is in the file. However, if the line does not exist remediation fails. It should be recognized that the lin eis missing and during remediation the line should be inserted rather than the remediation failing.

#### SCAP Security Guide Version:

0.1.80

#### Operating System Version:

SLES 15 SP7

#### Steps to Reproduce:

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#### Actual Results:

Remediation fails

#### Expected Results:

Remediation succeeds

#### Additional Information/Debugging Steps:
Discovered by @jgleissner