[d3d9] Add a forceModeHeights config option

[WinterSnowfall]

I've resurrected this, because the problem with the AquaNox games has come back to bite me even on my most recent Lunar Lake laptop. It seems that laptops in general (their screens in particular) simply expose too many modes for some games to be happy.

That can usually manifest as:

• higher resolutions are missing from in-game mode selection options
• lower resolutions get cut, which sometimes breaks the first-run configurations of games
• games overflow in their mode count logic and crash or refuse to start

There's always the option of coming up with an allow list of resolutions, similarly to how certain drivers apparently reduce excessive mode counts, but I'd rather have something user configurable, as we can't possibly account for all preferences and hardware combinations.