Fix memory leak when reloading unit params db

[guilherme-gm]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

Fixes a memory leak in unit params db when it was reloaded (e.g. through @reloadstatusdb). This was caused because the current implementation was not freeing the existing data before creating a new one.

I have also renamed status->unit_params_destroy to status->unit_params_destroy_entry to make its objective explicit, since I now added status->unit_params_clear_db too.

Thanks skyleo and Haru for the infos and suggestion on how to fix.

Issues addressed:
None