[core] Fix hp and mp visible gear latents

[TracentEden2]

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• [x] I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• [x] I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• [x] I have read and understood the Contributing Guide and the Code of Conduct.
• [x] I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

This PR adds the functionality for two rare types of latent gear. Specifically MP_UNDER_VISIBLE_GEAR and HP_OVER_VISIBLE_GEAR which are used by Uggalepih Pendant and Parade Gorget respectively. Retail testing can be see for example here and JP Wiki.

Still in draft as I figure out how this will interact with another PR I am making to fix other latent and HP issues.

Steps to test these changes

Calculate your HP or MP given only the +HP or +MP in the defined slots (SLOT_MAIN, SLOT_SUB, SLOT_RANGED, SLOT_AMMO, SLOT_BODY, SLOT_HANDS, SLOT_LEGS, SLOT_FEET) and then, with the pendant, for example, check your MATT at different MPs near 51%