Fix issues around scaleability and Runegraft of the Bound

Revisiting this code when looking over this PR makes me realize there are a few more hidden gotchas here.

1. Making a mod unscalable in a LIST mod doesn't do anything. An example of this would be "banners also cause enemies to take (%d+)%% increased damage". This code only checks for unscalable at the LIST level, not for each subMod: https://github.com/PathOfBuildingCommunity/PathOfBuilding/blob/78326a60910b00739c5f33be69cb140cd164a12c/src/Classes/ModStore.lua#L37-L50
2. Unscaleable mods get added twice. I tested "take no extra damage from critical strikes" and saw the value double (even though there is a hard cap on a lot of these unscalable mods

In short, I'll merge this PR but I needed to write this down somewhere so it can be refactored again, with proper test cases added for all these corner cases.

Originally posted by @Wires77 in https://github.com/PathOfBuildingCommunity/PathOfBuilding/issues/8977#issuecomment-3251710545

Beginne in src/Classes/ModStore.lua bei der verlinkten scaleability logic und verfolge, wie LIST mods und unscalable mods verarbeitet werden. Füge Testfälle für die Behandlung von unscalable pro subMod und die doppelte Anwendung hinzu und überprüfe anschließend, dass die betroffenen modifiers die erwarteten Werte erzeugen, ohne doppelt gezählt zu werden.