[Bug] Fix Flash Fire not showing message upon activation

[JSLveil]

What are the changes the user will see?

Flash Fire will now send a Fire-boosting message once upon activation and an immunity message every time after.

Why am I making these changes?

Closes #4058

What are the changes from a developer perspective?

• data/ability: Added a condition in TypeImmunityAddBattlerTagAbAttr (which only Flash Fire uses but whatever) to check if the effect has already been applied. If no, display the new Flash Fire message and if yes, display the standard immunity message.
• locales/en/ability-trigger: Added new Flash Fire message that generalizes to any move type if required.

Screenshots/Videos

Before

PreFix.mp4

After

AfterFix.mp4

How to test the changes?

Activate Flash Fire. I used overrides.

Checklist

• I'm using beta as my base branch
• I wasn't before though, whoops
• 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?
• If I have text, did I make it translatable and add a key in the English locale file(s)?
• Not sure about this one actually, but I think I did everything right unless I'm forgetting something.
• 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]

Uh, you forgot to add a description to the PR.

[SangaraSorama]

The locales PR adding the line to flash fire is merged

[DayKev]

I think it's good, but apparently testing locales changes is difficult. Need to figure out how to force the locales update to appear locally...

[innerthunder]

Flash Fire's message should be contained within its respective tag (i.e. in the onAdd function). This implementation isn't really scalable since it only displays the right message when the attribute is used for Flash Fire