[Sprite] Add female Ursaring variant palettes

[chaosgrimmon]

What are the changes?

Previously, female Ursaring did not have variant palettes, and so showed up as the standard base shiny. This PR adds the palettes, allowing the intended shiny colours.

Why am I doing these changes?

Reported here, as causing issues on Ydarissep's dex.

What did change?

Added the front and back palette .jsons. Also added the necessary entries to \variant\_masterlist.json for the game to recognise those palettes.

Screenshots/Videos

Before

After

How to test the changes?

Checklist

• I'm using beta as my base branch
• 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 considered writing automated tests for the issue?
• 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?