Fix TabBar doesn't use labelStyle & unselectedLabelStyle color

[TahaTesser]

Fixes TabBar labelStyle.color and unselectedLabelStyle.color does not take effect

Code sample

expand to view the code sample

import 'package:flutter/material.dart';

/// Flutter code sample for [TabBar].

const Color labelColor = Color(0xFFFF0000);
const Color unselectedLabelColor = Color(0x95FF0000);
const TextStyle labelStyle = TextStyle(
  color: Color(0xff0000ff),
  fontWeight: FontWeight.bold,
);
const TextStyle unselectedLabelStyle = TextStyle(
  color: Color(0x950000ff),
  fontStyle: FontStyle.italic,
);

void main() => runApp(const TabBarApp());

class TabBarApp extends StatelessWidget {
  const TabBarApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: const TabBarExample(),
    );
  }
}

class TabBarExample extends StatelessWidget {
  const TabBarExample({super.key});

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      initialIndex: 1,
      length: 3,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('TabBar Sample'),
          bottom: const TabBar(
            // labelColor: labelColor,
            // unselectedLabelColor: unselectedLabelColor,
            labelStyle: labelStyle,
            unselectedLabelStyle: unselectedLabelStyle,
            tabs: <Widget>[
              Tab(
                icon: Icon(Icons.cloud_outlined),
                text: 'Cloudy',
              ),
              Tab(
                icon: Icon(Icons.beach_access_sharp),
                text: 'Sunny',
              ),
              Tab(
                icon: Icon(Icons.brightness_5_sharp),
                text: 'Rainy',
              ),
            ],
          ),
        ),
        body: const TabBarView(
          children: <Widget>[
            Center(
              child: Text("It's cloudy here"),
            ),
            Center(
              child: Text("It's rainy here"),
            ),
            Center(
              child: Text("It's sunny here"),
            ),
          ],
        ),
      ),
    );
  }
}

When labelStyle and unselectedLabelStyle are specified with a color.

Before

After

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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[HansMuller]

LGTM

[HansMuller]

It's a shame that this is so complicated although it's likely that most developers will expect these sorts of overrides to work intuitively.