Fix usage of old ERR_FAIL macro when new variant intended.

[profan]

So I managed to get this sin into master with it still building successfully somehow, I'd have expected this to cause a build failure:

godot/platform/windows/os_windows.cpp

Lines 2744 to 2750 in 3ea33c0

	SendMessage(hWnd, WM_SETICON, ICON_SMALL, (LPARAM)icon_small);
	err = GetLastError();
	ERR_FAIL_COND(err, "Error setting ICON_SMALL: " + format_error_message(err) + ".");
	SendMessage(hWnd, WM_SETICON, ICON_BIG, (LPARAM)icon_big);
	err = GetLastError();
	ERR_FAIL_COND(err, "Error setting ICON_BIG: " + format_error_message(err) + ".");

I went over the last code changes again and I think I didn't leave any more instances like this in.

Relates to #31227

[profan]

In fact, looking at the appveyor build reveals this: https://ci.appveyor.com/project/akien-mga/godot/builds/26582781#L97 (where it's just a warning instead of an error, argh!)

[akien-mga]

Thanks!