fix: init cluster health default status to green avoid nil panic

[luohf-infinilabs]

What does this PR do

This pull request includes a small change to the core/elastic/actions.go file. The change ensures that when the Init method is called with a true health parameter, the Health field is initialized with a default ClusterHealth status of "green" if it is currently nil.

• core/elastic/actions.go: Added initialization of Health field with a default ClusterHealth status of "green" when health is true and Health is nil.

Rationale for this change

Standards checklist

• The PR title is descriptive
• The commit messages are semantic
• Necessary tests are added
• Updated the release notes
• Necessary documents have been added if this is a new feature
• Performance tests checked, no obvious performance degradation