Remove padding from autofill CVC/CVV verification screen checkbox

BUG=473250

Review URL: https://codereview.chromium.org/1091853002

Cr-Commit-Position: refs/heads/master@{#325520}

chrome/android/java/res/layout/autofill_card_unmask_prompt.xml

@@ -152,7 +152,6 @@
                 android:layout_centerVertical="true"
                 android:layout_marginStart="17dp"
                 android:layout_marginEnd="10dp"
-                android:paddingStart="7dp"
                 android:textSize="14sp"
                 android:textColor="@color/explanation_text_color"
                 android:text="@string/autofill_card_unmask_prompt_storage_checkbox" />