Uses Kubernetes API conventions to create or update a resource

What does this MR do?

It partially resolves #29959 (closed).

When creating or updating Kubernetes resources via KubeClient we use a pattern which first checks if the resource exists, followed by calling create_[resource] or update_[resource] based on the result of the initial request.

As shown in this thread, just a single update_[resource] call will have the same effect, and will also remove an unnecessary request to the cluster.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team