[Sprite] Shiny Spritzee colour correction

[chaosgrimmon]

What are the changes?

Only one frame of shiny Spritzee's sprite was the correct colour. This PR fixes that, and cleans up the palettes in general.

Why am I doing these changes?

Previously reported.

What did change?

The shiny sprite's palette was cleaned up, removing the old, incorrect colours. As a preemptive measure, the same cleanup was performed on the non-shiny sprite, in preparation for future variants.

Screenshots/Videos

Before

After

How to test the changes?

As the issue only concerned front experimental animations, the change can be seen on any sufficiently-completed savefile.

Checklist

• There is no overlap with another PR?
• The PR is self-contained and cannot be split into smaller PRs?
• Have I provided a clear explanation of the changes?
• Have I tested the changes (manually)?
  • Are all unit tests still passing? (npm run test)
• Are the changes visual?
  • Have I provided screenshots/videos of the changes?