Fix SettingsTheme alignment below v27

- Simply removes the preferenceTheme attribute to fix the issue
As per Preference 1.0.0-rc01 release notes: PreferenceThemeOverlay has been updated to the latest material theme. If no custom theme is provided, PreferenceThemeOverlay is used as the default theme.

Author: lukeswitz

src/main/res/values/styles.xml

@@ -20,7 +20,6 @@
         <item name="colorAccent">@color/colorAccent</item>
         <item name="android:textColorPrimary">@color/primary_text</item>
         <item name="android:textColorSecondary">@color/secondary_text</item>
-        <item name="preferenceTheme">@style/PreferenceThemeOverlay.v14.Material</item>
     </style>
 
     <!-- Style for an Preference Entry -->