In this commit, we add unit tests for the `ValidationAdmission`
webhook specifically for the `ClusterOverridePolicy` resource. These
tests ensure that the webhook correctly handles various admission
scenarios:
- Tests the behavior when decoding the request object fails, verifying
that the admission is denied with an approriate error message.
- Validates that the webhook denies admission when encountering invalid
label values in the `ClusterOverridePolicy` spec, ensuring proper error messaging.
- Confirms that valid `ClusterOverridePolicy` objects are admissionly allowed
without errors.
Signed-off-by: Mohamed Awnallah <mohamedmohey2352@gmail.com>