Remove special theming for CardUnmaskPrompt since it's now automatic

chrome/android/java/res/values-v17/styles.xml

Index: chrome/android/java/res/values-v17/styles.xml
diff --git a/chrome/android/java/res/values-v17/styles.xml b/chrome/android/java/res/values-v17/styles.xml
index 10ee0e917adcbf014dd6c981547e6a378bc7e46b..ef22bc52f16e6cb9ceac5cfc22ab64776b0369c3 100644
--- a/chrome/android/java/res/values-v17/styles.xml
+++ b/chrome/android/java/res/values-v17/styles.xml
@@ -4,24 +4,6 @@
      found in the LICENSE file. -->
 
 <resources>
-    <!-- A theme for alert dialogs. The colors are copied from MainTheme, and the window
-         dimensions are copied from *.MinWidth theme variants. Sadly there is no
-         AppCompat.Light.Dialog.Alert or even AppCompat.Light.Dialog.MinWidth. -->
-    <style name="AlertDialogTheme" parent="Theme.AppCompat.Light.Dialog">
-        <item name="android:textColorHighlight">@color/text_highlight_color</item>
-        <item name="android:windowMinWidthMajor">@android:dimen/dialog_min_width_major</item>
-        <item name="android:windowMinWidthMinor">@android:dimen/dialog_min_width_minor</item>
-
-        <!--  Overriding AppCompat values -->
-        <item name="colorAccent">@color/light_active_color</item>
-        <item name="colorControlActivated">@color/light_active_color</item>
-        <item name="colorControlNormal">@color/light_normal_color</item>
-        <item name="colorPrimary">@color/light_active_color</item>
-
-        <!-- Default TintedImageButton tint -->
-        <item name="tint">@color/dark_mode_tint</item>
-    </style>
-
     <!-- Preferences -->
     <style name="PreferencesTheme" parent="ThemeWithActionBar">
         <item name="android:textColorLink">@color/pref_accent_color</item>