[Material] Remove inherit: false on default TextStyle in bottom navigation bar (#32727)

packages/flutter/lib/src/material/bottom_navigation_bar.dart

@@ -778,7 +778,7 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
   // If the given [TextStyle] has a non-null `fontSize`, it should be used.
   // Otherwise, the [selectedFontSize] parameter should be used.
   static TextStyle _effectiveTextStyle(TextStyle textStyle, double fontSize) {
-    textStyle ??= const TextStyle(inherit: false);
+    textStyle ??= const TextStyle();
     // Prefer the font size on textStyle if present.
     return textStyle.fontSize == null ? textStyle.copyWith(fontSize: fontSize) : textStyle;
   }

packages/flutter/test/material/bottom_navigation_bar_test.dart

@@ -106,10 +106,10 @@ void main() {
     final TextStyle unselectedIcon = _iconStyle(tester, Icons.access_alarm);
     expect(selectedFontStyle.color, equals(primaryColor));
     expect(selectedFontStyle.fontSize, selectedFontSize);
-    expect(selectedFontStyle.fontWeight, isNull);
+    expect(selectedFontStyle.fontWeight, equals(FontWeight.w400));
     expect(selectedFontStyle.height, isNull);
     expect(unselectedFontStyle.color, equals(captionColor));
-    expect(unselectedFontStyle.fontWeight, isNull);
+    expect(unselectedFontStyle.fontWeight, equals(FontWeight.w400));
     expect(unselectedFontStyle.height, isNull);
     // Unselected label has a font size of 14 but is scaled down to be font size 12.
     expect(