Upgrade to Flutter 3.16 (#297)

* MIgrate to new APIs

* Use Material 3 by default

* Migrate to onPopInvoked

* Fix tab bar alignment

* Upgrade packages

* Update pods

* Fix chat pop behavior on iOS

lib/theme.dart

@@ -16,7 +16,6 @@ class FrostyThemes {
         : Colors.grey.shade800;
 
     return ThemeData(
-      useMaterial3: true,
       fontFamily: 'Inter',
       brightness: brightness,
       colorSchemeSeed: colorSchemeSeed,
@@ -57,6 +56,7 @@ class FrostyThemes {
       ),
       tabBarTheme: const TabBarTheme(
         dividerColor: Colors.transparent,
+        tabAlignment: TabAlignment.start,
       ),
       tooltipTheme: TooltipThemeData(
         padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),