fix(ui): 修正六屏顶栏与内容间距

test/drama_detail/drama_detail_view_test.dart

@@ -33,6 +33,21 @@ void main() {
     await tester.pumpAndSettle();
 
     expect(tester.getSize(find.byKey(const Key('detail-hero'))).height, 190);
+    expect(
+      tester.getSize(find.byKey(const Key('detail-back'))),
+      const Size(36, 36),
+    );
+    expect(
+      tester
+          .widget<Icon>(
+            find.descendant(
+              of: find.byKey(const Key('detail-back')),
+              matching: find.byType(Icon),
+            ),
+          )
+          .size,
+      18,
+    );
     expect(find.byKey(const Key('detail-cta')), findsOneWidget);
     expect(tester.getSize(find.byKey(const Key('detail-cta'))).height, 40);
     expect(find.byKey(const Key('detail-episode-chip-1')), findsOneWidget);