[Fix] Change damageType LIGHTNING to THUNDER

[Xaver-DaRed]

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• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• 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?

We had both xi.damageType.LIGHTNING and xi.damageType.THUNDER cases of damageType existing in the code. One had to be chosen.

"But why was THUNDER chosen over LIGHTNING? I liked LIGHTNING"
Because THUNDER is shorter AND aligns with the element naming of xi.element table.

Steps to test these changes

Some things may work properly now?