[NavigationRail] Add label padding for when the label is long enough to reach the sides of the nav rail

PiperOrigin-RevId: 584069016

Author: imhappi

lib/java/com/google/android/material/navigationrail/res/layout/mtrl_navigation_rail_item.xml

@@ -52,6 +52,8 @@
         android:duplicateParentState="true"
         android:ellipsize="end"
         android:maxLines="1"
+        android:paddingStart="@dimen/m3_navigation_rail_label_padding_horizontal"
+        android:paddingEnd="@dimen/m3_navigation_rail_label_padding_horizontal"
         android:textSize="@dimen/mtrl_navigation_rail_text_size" />
     <TextView
         android:id="@id/navigation_bar_item_large_label_view"
@@ -61,6 +63,8 @@
         android:ellipsize="end"
         android:maxLines="1"
         android:textSize="@dimen/mtrl_navigation_rail_active_text_size"
+        android:paddingStart="@dimen/m3_navigation_rail_label_padding_horizontal"
+        android:paddingEnd="@dimen/m3_navigation_rail_label_padding_horizontal"
         android:visibility="invisible" />
   </com.google.android.material.internal.BaselineLayout>
 </merge>

lib/java/com/google/android/material/navigationrail/res/values/dimens.xml

@@ -37,5 +37,6 @@
   <dimen name="m3_navigation_rail_item_active_indicator_width">@dimen/m3_comp_navigation_rail_active_indicator_width</dimen>
   <dimen name="m3_navigation_rail_item_active_indicator_height">@dimen/m3_comp_navigation_rail_active_indicator_height</dimen>
   <dimen name="m3_navigation_rail_item_active_indicator_margin_horizontal">4dp</dimen>
+  <dimen name="m3_navigation_rail_label_padding_horizontal">2dp</dimen>
 
 </resources>