[Download-Rename] Fix an extra margin in rename extension dialog text view.

 - Deleted the redundant style appled in dialog linear layout.

Bug: 1012450
Change-Id: Ice1accff7bc3bc09dc625c622a679328be133d1b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1846470Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Auto-Submit: Hesen Zhang <hesen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704831}

chrome/android/java/res_download/layout/download_rename_extension_custom_dialog.xml

@@ -9,8 +9,7 @@
     <LinearLayout
         android:orientation="vertical"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        style="@style/AlertDialogContent">
+        android:layout_height="wrap_content">
 
         <TextView
             android:id="@+id/subtitle"