[fenix] For https://github.com/mozilla-mobile/fenix/issues/6607 Update button theming in no tab pane

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/viewholders/NoContentMessageWithActionViewHolder.kt

@@ -36,7 +36,7 @@ class NoContentMessageWithActionViewHolder(
         with(view.context) {
 
             if (buttonIcon != 0 || buttonText != 0) {
-                view.add_tab_button.apply {
+                view.add_new_tab_button.apply {
                     isVisible = true
                     setIcon(getDrawable(buttonIcon))
                     text = getString(buttonText)

app/src/main/res/layout/no_content_message_with_action.xml

@@ -37,7 +37,7 @@
         tools:text="@tools:sample/lorem" />
 
     <com.google.android.material.button.MaterialButton
-        android:id="@+id/add_tab_button"
+        android:id="@+id/add_new_tab_button"
         style="@style/ThemeIndependentMaterialGreyButton"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"