[Test] Add test for final boss fight phase switch

[MokaStitcher]

What are the changes the user will see?

No changes hopefully, this just adds a test and makes a tiny refactor along the way

Why am I making these changes?

There was a test marked as 'todo' to check that the final boss switched phase properly when its final shield gets broken.
Since there have been issues in the past with it not working with status damage, tests were added for both status and direct damage

What are the changes from a developer perspective?

• Implemented test marked as 'todo' for final boss switching to its second phase in src/test/final_boss.test.ts
• This required being able to skip through the dialog after the first phase. To do this I updated the helper function gameManager.runToFinalBossEncounter to mock ui.shouldSkipDialogue instead of what it was doing before, so that all dialog gets skipped and not just the one before the fight
• This meant in ui.showDialog the function had to actually be called (the code was already doing the same checks as shouldSkipDialogue rather than calling it), so I did that

Screenshots/Videos

N/A

How to test the changes?

npm run test src/test/final_boss.test.ts

You could play a bit and make sure the dialogue gets skipped if the setting is enabled like before

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?
• If I have text, did I make it translatable and add a key in the English locale file(s)?
• 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?

[DayKev]

Couple comments/changes here: MokaStitcher#1