For #7975 - Added a progress bar according to specs

app/src/main/java/org/mozilla/fenix/migration/MigrationProgressActivity.kt

@@ -78,6 +78,7 @@ class MigrationProgressActivity : AbstractMigrationProgressActivity() {
             setBackgroundColor(ContextCompat.getColor(context, R.color.button_text_color))
             setTextColor(ContextCompat.getColor(context, R.color.white_color))
         }
+        migration_button_progress_bar.visibility = View.INVISIBLE
         // Keep the results list up-to-date.
         statusAdapter.submitList(results.toItemList())
     }

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

@@ -77,6 +77,8 @@
                 android:enabled="false"
                 android:minWidth="200dp"
                 android:text="@string/migration_updating_app_button_text"
+                android:paddingStart="@dimen/migration_button_padding"
+                android:paddingEnd="@dimen/migration_button_padding"
                 android:textColor="@color/button_text_color"
                 android:textAllCaps="false"
                 android:background="@color/grey_button_color"
@@ -85,6 +87,19 @@
                 app:layout_constraintStart_toStartOf="parent"
                 tools:text="Updating Firefox…" />
 
+        <ProgressBar
+                android:id="@+id/migration_button_progress_bar"
+                style="@style/Widget.AppCompat.ProgressBar"
+                android:layout_width="24dp"
+                android:layout_height="24dp"
+                android:layout_marginStart="4dp"
+                android:layout_marginTop="8dp"
+                android:layout_marginBottom="8dp"
+                app:layout_constraintBottom_toBottomOf="@+id/migration_button"
+                app:layout_constraintDimensionRatio="h,1:1"
+                app:layout_constraintStart_toStartOf="@+id/migration_button"
+                app:layout_constraintTop_toTopOf="@+id/migration_button" />
+
     </androidx.constraintlayout.widget.ConstraintLayout>
 
 </ScrollView>
\ No newline at end of file

app/src/main/res/values/dimens.xml

@@ -103,5 +103,7 @@
     <dimen name="locale_item_title_size">16sp</dimen>
     <dimen name="locale_item_subtitle_size">12sp</dimen>
 
+    <!--Migration Activity-->
+    <dimen name="migration_button_padding">32dp</dimen>
 
 </resources>