Need to remove triggers from game state when removing an ability from a permanent

[xenohedron]

Existing TODO originally noted in #6585

When adding an ability to a permanent, if it's a triggered ability, it also gets added directly to the game state. This is necessary for triggering correctly when leaving the battlefield. However, the code that removes abilities from permanents doesn't account for this, but needs to. I noticed this very clearly with my mutate implementation in #14900 . While the workaround there was very simple, it's probably better to fix the underlying discrepancy if possible.

mage/Mage/src/main/java/mage/game/permanent/PermanentImpl.java

Lines 464 to 469 in e3e948e

	// triggered abilities must be added to the state().triggers
	// still as long as the prev. permanent is known to the LKI (e.g. Showstopper) so gained dies triggered ability will trigger
	if (game != null) {
	// game is null in cards viewer window (MageBook)
	game.getState().addAbility(copyAbility, sourceId, this);
	}

mage/Mage/src/main/java/mage/game/permanent/PermanentImpl.java

Lines 479 to 483 in e3e948e

	@Override
	public void removeAllAbilities(UUID sourceId, Game game) {
	// TODO: what about triggered abilities? See addAbility above -- triggers adds to GameState
	abilities.clear();
	}

mage/Mage/src/main/java/mage/game/permanent/PermanentImpl.java

Lines 499 to 500 in e3e948e

	// TODO: what about triggered abilities? See addAbility above -- triggers adds to GameState
	toRemove.forEach(r -> abilities.remove(r));

TriggeredAbilities has a method for removing all abilities from a particular source. But not currently a way to remove an arbitrary ability.

mage/Mage/src/main/java/mage/abilities/TriggeredAbilities.java

Lines 320 to 322 in e3e948e

	public void removeAbilitiesOfSource(UUID sourceId) {
	keySet().removeIf(key -> key.endsWith(sourceId.toString()));
	}

[Grath]

I wonder if this is also the cause of the vestigial triggers from the top half on Meld permanents?