Fix formatting in BottomAppBar test (#115520)

This PR made a few mistakes on formatting: https://github.com/flutter/flutter/pull/115175

packages/flutter/test/material/bottom_app_bar_test.dart

@@ -85,7 +85,6 @@ void main() {
     );
   }, skip: isBrowser); // https://github.com/flutter/flutter/issues/44572
 
-
   testWidgets('Custom Padding', (WidgetTester tester) async {
     const EdgeInsets customPadding = EdgeInsets.all(10);
     await tester.pumpWidget(
@@ -98,9 +97,9 @@ void main() {
                 alignment: Alignment.bottomCenter,
                 child: BottomAppBar(
                   padding: customPadding,
-                    child:ColoredBox(
-                      color:Colors.green,
-                      child:SizedBox(width: 300, height: 60),
+                  child: ColoredBox(
+                    color: Colors.green,
+                    child: SizedBox(width: 300, height: 60),
                   ),
                 ),
               ),
@@ -130,9 +129,9 @@ void main() {
                 alignment: Alignment.bottomCenter,
                 child: BottomAppBar(
                   padding: customPadding,
-                    child:ColoredBox(
-                      color:Colors.green,
-                      child:SizedBox(width: 300, height: 60),
+                  child: ColoredBox(
+                    color: Colors.green,
+                    child: SizedBox(width: 300, height: 60),
                   ),
                 ),
               ),