test(kubernetes): cover attribute handler's main paths

[afsuyadi]

Description

What changes are being made?
I add some unit tests for Kubernetes with 4 cases:
a. test_kind_not_found: Ask the handler for a ConfigMap, but input.yml has no ConfigMap in it.
-> Expects: an error ("kind:ConfigMap is not found") plus a ProviderError with severity_value == 1.

b. test_plain_path: Asks for metadata.name on the Role resource (a path with no *), and there is exactly one Role.
-> Expects: a single plain value back, "access-role", not wrapped in a list.

c. test_wildcard_path: Asks for spec.selector.matchLabels.* on the Deployment resource. The * symbol means "give me every value at this level".
-> Expects: a list of all matched values, ["wfs-demo", "wfs-demp"].

d. test_missing_attribute: Asks for metadata.labels on RoleBinding, but that resource has no labels key at all.
-> Expects: None. Proving the handler doesn't crash on a missing field, it just reports "nothing here".

Which issues or tickets does this PR close or relate to?
Related issue: fixes #405

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Other (please specify): Test cases for Kubernetes

Checklist

• Code has been linted.
• Documentation has been updated (if needed).
• Tests have been added or updated (if needed).
• Any breaking changes have been communicated to the team.

Screenshots or Recordings (if applicable)

Additional Information