Plugin enhancement suggestions

Hi,

After trying this plugin out, I had a few suggestions for improvements:

1. Usability
- Every secret requires you to specify k8s cluster information. Can we instead provide a dropdown with k8s-cluster-profiles?

2. Error messages and field descriptions
- The namespace field description needs to be fixed, it’s describing the field incorrectly at the moment.
- The plugin returns an incorrect and confusing error when the token provided doesn’t have permissions to read secrets.
- Currently, if the cluster URL is misconfigured, or the secret doesn’t exist, you get one message. This makes it confusing to know which of these two error conditions current exists. Split into two messages, check to see if you can connect to the cluster first, then see if you can find the secret.
```Either the connection with kubernetes cluster could not be established or the kubernetes secret does not exists.```
- It is not obvious that you need to enable permissions while setting up a secret. The error message “” doesn’t point you to the secrets configuration. In the least, consider improving the error message.
```Job for pipeline 'ganeshpl-test/10/defaultStage/1/defaultJob' failed due to errors: Job: 'defaultJob' in Pipeline: 'ganeshpl-test' and Pipeline Group: 'sample' does not have permission to refer to secrets using secret config 'sheroys-secrets’```

Start by locating the plugin code that handles Kubernetes cluster configuration, namespace descriptions, secret lookup, and permission-related errors. Review how cluster profiles are configured and how connection, missing-secret, and permission failures are currently reported. Done means the requested usability and message distinctions are addressed and verified with relevant tests; the issue names no specific files or tests.

Written by the indexing model from the issue text.