steamcompmgr: Consolidate duped logic into ShouldDrawCursor

src/steamcompmgr.cpp

@@ -2225,6 +2225,16 @@ static void paint_pipewire()
 #endif
 
 gamescope::ConVar<int> cv_cursor_composite{ "cursor_composite", 1, "0 = Never composite a cursor. 1 = Composite cursor when not nested. 2 = Always composite a cursor manually" };
+bool ShouldDrawCursor()
+{
+	if ( cv_cursor_composite == 2 )
+		return true;
+
+	if ( cv_cursor_composite == 0 )
+		return false;
+
+	return g_bForceRelativeMouse || !GetBackend()->GetNestedHints();
+}
 
 static void
 paint_all(bool async)
@@ -2441,10 +2451,8 @@ paint_all(bool async)
 		global_focus.cursor->undirty();
 	}
 
-	bool bForceHideCursor = ( ( GetBackend()->GetNestedHints() && !bSteamCompMgrGrab ) || cv_cursor_composite == 0 ) && cv_cursor_composite != 2;
-
 	// Draw cursor if we need to
-	if (input && !bForceHideCursor) {
+	if (input && !ShouldDrawCursor()) {
 		global_focus.cursor->paint(
 			input, w == input ? override : nullptr,
 			&frameInfo);