Fix chip label not vertically aligned when using sub themes.

[davidmartos96]

Fixes #305

Hello!
After upgrading to v8 I noticed that text chips were not aligned vertically.
After investigation it turned out to be that the following text style wasn't using the leadingDistribution as .even and textBaseline as .alphabetic.

flex_color_scheme/lib/src/flex_sub_themes.dart

Line 1995 in bbae097

final TextStyle baseLabelStyle = (labelStyle ?? const TextStyle()).copyWith(

Those properties come from the typography text theme geometry, and Flutter applies those styles when doing Theme.of(context), and inside ThemeData.localize is called.
The englishLike textTheme in the typography contains those properties.

The fix I propose is basically doing the same TextStyle.merge that Flutter does when calling Theme.of(context).

Theme.of(context)
https://github.com/flutter/flutter/blob/f6ff1529fd6d8af5f706051d9251ac9231c83407/packages/flutter/lib/src/material/theme.dart#L139

ThemeData.localize
https://github.com/flutter/flutter/blob/f6ff1529fd6d8af5f706051d9251ac9231c83407/packages/flutter/lib/src/material/theme_data.dart#L1763-L1766

To reproduce the issue you can try the following code with and without subThemesData. Hot reload won't work here, you need to hot restart to see the actual difference.

import 'package:flex_color_scheme/flex_color_scheme.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    final theme = FlexThemeData.dark(
      scheme: FlexScheme.mandyRed,
      typography: Typography.material2021(),
      subThemesData: FlexSubThemesData(),
    );

    return MaterialApp(title: 'Flutter Demo', theme: theme, home: MyHomePage());
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            InputChip(
              avatar: Icon(Icons.emoji_emotions_rounded),
              onPressed: () {},
              label: ColoredBox(color: Colors.red, child: Text('My Chip')),
            ),
          ],
        ),
      ),
    );
  }
}

Before

After

This also automatically fixes the chip label fontWeight not using w500, which was forgotten in the copyWith linked above.

[davidmartos96]

@rydmike Hello Mike!
Just wondering if you had a chance to look at this? Or if it was hidden in your notifications.