[UI/UX] Fix showing form names and types

[Wlowscha]

What are the changes the user will see?

• Form names are displayed properly
• Form types are shown correctly when scrolling through the tray
• Unobtainable forms are not shown

What are the changes from a developer perspective?

Added a new isUnobtainable attribute in PokemonForm which can be checked by the dex, so far given to forms of Marshadow, Arceus, Ploteageist and its prevolution.

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 tested the changes manually?
• Are all unit tests still passing? (npm run test)
• Have I provided screenshots/videos of the changes (if applicable)?
  • Have I made sure that any UI change works for both UI themes (default and legacy)?

[Wlowscha]