enhance: it's not necessary to invalidate measure of LineModifyTypeMargin when data context of text-diff-view changed

Signed-off-by: leo <longshuang@msn.cn>

src/Views/TextDiffView.axaml.cs

@@ -203,7 +203,7 @@ namespace SourceGit.Views
             protected override void OnDataContextChanged(EventArgs e)
             {
                 base.OnDataContextChanged(e);
-                InvalidateMeasure();
+                InvalidateVisual();
             }
         }