Tracker: Revert to previous CalcRectCommon bottom calc

... in list mode. Fixes #12997

This bug was introduced in hrev50528 along with new 32x32 icon size
in list mode. I'm not sure what I was thinking on this particular
line but reverting it seems to fix the problem and logically the
original code makes sense.

src/kits/tracker/TextWidget.cpp

@@ -175,8 +175,7 @@ BTextWidget::CalcRectCommon(BPoint poseLoc, const BColumn* column,
 				break;
 		}
 
-		result.bottom = poseLoc.y
-			+ roundf((view->ListElemHeight() + view->FontHeight()) / 2);
+		result.bottom = poseLoc.y + (view->ListElemHeight() - 1);
 	} else {
 		if (view->ViewMode() == kIconMode) {
 			// large/scaled icon mode