Fixes KIs required for a Smooth Velvet (51) and Neutralizing Silver

[clanofartisans]

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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?

• Adds the missing KI required for the level 51 version of the Smooth Velvet synth. (Requires Cloth Purification)
• Corrects the KI required for the Neutralizing Silver synth. (Requires Gold Purification, not Gold Ensorcellment)

Steps to test these changes

Try the synths with the incorrect and correct KIs.