Removed deprecated graphics settings/performance menu options. Updated automated test accordingly.

Signed-off-by: Chris Galvan <chgalvan@amazon.com>

Code/Editor/Style/GraphicsSettingsDialog.qss

@@ -1,25 +0,0 @@
-/*
- * Copyright (c) Contributors to the Open 3D Engine Project. For complete copyright and license terms please see the LICENSE at the root of this distribution.
- * 
- * SPDX-License-Identifier: Apache-2.0 OR MIT
- *
- */
-
-#GraphicsSettingsDialog QHeaderView::section
-{
-        background: #2D2D2D;
-}
-
-#GraphicsSettingsDialog QHeaderView::down-arrow
-{
-    width: 14px;
-    height: 14px;
-    image: url(:/Gallery/Delete.svg);
-}
-
-#GraphicsSettingsDialog QHeaderView::up-arrow
-{
-    width: 14px;
-    height: 14px;
-    image: url(:/Gallery/Delete.svg);
-}

Code/Editor/Style/resources.qrc

@@ -3,6 +3,5 @@
     <file alias="Assets/Editor/Style/Editor.qss">Editor.qss</file>
     <file alias="Assets/Editor/Style/EditorPreferencesDialog.qss">EditorPreferencesDialog.qss</file>
     <file alias="Assets/Editor/Style/LayoutConfigDialog.qss">LayoutConfigDialog.qss</file>
-    <file alias="Assets/Editor/Style/GraphicsSettingsDialog.qss">GraphicsSettingsDialog.qss</file>
 </qresource>
 </RCC>