Fix ImGui spam of ShowCursor/HideCursor

[WSSDude]

Also makes sure that we actually have 200 descriptors for texture, we allocated only 3 (ImGui really needs only 1 though per viewport, we have one in main) but allowed up to 200.

[WSSDude]

Setting ImGuiConfigFlags_NoMouseCursorChange prevents ImGui from setting cursor each frame in Win32 backend, which was the primary cause for the Show/HideCursor not working before after single call. And with the latest addition of ForceCursor game function, this is not needed anymore and is overall cleaner as the game cannot randomly hide our cursor and it ensures proper clipping rect for it.