fix: Unable to use hyphen in JSON path for oidc-groups-claim option

[rd-danny-fleer]

Description

• Removed dependency "github.com/ohler55/ojg/jp"
• Always evaluate claim as string literal first and as JSON path as fallback

Motivation and Context

Fix #2618

I know there might be better solutions, like implementing a feature flag and an additional option to control if oidc-groups-claims should be evaluated as string or JSON path.
However such a change might be breaking and I didn't want to anticipate the decision for an alternative. Therefore I implemented a simple solution in the first step.

How Has This Been Tested?

Added additional tests.

Checklist:

• My change requires a change to the documentation or CHANGELOG.
• I have updated the documentation/CHANGELOG accordingly.
• I have created a feature (non-master) branch for my PR.
• I have written tests for my code changes.