Implement validation for resource kind in get_cluster_resources_raw_data

[coderabbitai]

As discussed in PR #8 and this comment, there is a need to implement validation in the get_cluster_resources_raw_data function to handle the following cases:

1. No resource kind found among aliases.
2. Resource kind found, but no such resource YAML exists in the collected must-gather.

Requested by @jpeimer.