#120577

#120932

AppBar, SliverAppBar, and AppBarTheme updates

Supported by Flutter Fix: yes

In v2.4, several changes were made ot the app bar classes and their themes to
better align with Material Design. Several properties were deprecated at that
time and have been removed.

For AppBar, SliverAppBar and AppBarTheme:

brightness has been removed, and is replaced by systemOverlayStyle

textTheme has been removed, and is replaced by either toolbarTextStyle or titleTextStyle.

backwardsCompatibility can be removed, as it was a temporary migration flag for these properties.

Additionally, AppBarTheme.color was removed, with AppBarTheme.backgroundColor
as its replacement.

Migration guide

Code before migration:

var

toolbarTextStyle

TextStyle