Fix rendering of icons

Author: shana

src/GitHub.VisualStudio/Base/TeamExplorerNavigationItemBase.cs

@@ -45,11 +45,9 @@ void OnThemeChanged()
         {
             try
             {
-                var color = VSColorTheme.GetThemedColor(EnvironmentColors.ToolWindowTextColorKey);
-                var brightness = color.GetBrightness();
-                var dark = brightness > 0.5f;
-
-                Icon = SharedResources.GetDrawingForIcon(octicon, dark ? Colors.DarkThemeNavigationItem : Colors.LightThemeNavigationItem, dark ? "dark" : "light");
+                var theme = Colors.DetectTheme();
+                var dark = theme == "Dark";
+                Icon = SharedResources.GetDrawingForIcon(octicon, dark ? Colors.DarkThemeNavigationItem : Colors.LightThemeNavigationItem, theme);
             }
             catch (ArgumentNullException)
             {

src/GitHub.VisualStudio/Services/SharedResources.cs

@@ -27,7 +27,6 @@ public static DrawingBrush GetDrawingForIcon(Octicon icon, Brush colorBrush, str
                 Drawing = new GeometryDrawing()
                 {
                     Brush = colorBrush,
-                    Pen = new Pen(colorBrush, 1.0).FreezeThis(),
                     Geometry = OcticonPath.GetGeometryForIcon(icon).FreezeThis()
                 }
                 .FreezeThis(),

src/GitHub.VisualStudio/TeamExplorer/Connect/GitHubInvitationSection.cs

@@ -64,11 +64,9 @@ void OnThemeChanged()
         {
             try
             {
-                var color = VSColorTheme.GetThemedColor(EnvironmentColors.ToolWindowTextColorKey);
-                var brightness = color.GetBrightness();
-                var dark = brightness > 0.5f;
-
-                Icon = SharedResources.GetDrawingForIcon(Octicon.mark_github, dark ? Helpers.Colors.DarkThemeNavigationItem : Helpers.Colors.LightThemeNavigationItem, dark ? "dark" : "light");
+                var theme = Helpers.Colors.DetectTheme();
+                var dark = theme == "Dark";
+                Icon = SharedResources.GetDrawingForIcon(Octicon.mark_github, dark ? Colors.White : Helpers.Colors.LightThemeNavigationItem, theme);
             }
             catch (ArgumentNullException)
             {