Revert "feat(ui_auth): add a way to customize ErrorText message (firebase#119)"

This reverts commit a36884d.

Author: ShahoodulHassan

packages/firebase_ui_auth/lib/src/widgets/error_text.dart

@@ -36,28 +36,6 @@ String? localizedErrorText(
 /// A widget which displays error text for a given Firebase error code.
 /// {@endtemplate}
 class ErrorText extends StatelessWidget {
-  /// A way to customize localized error messages.
-  ///
-  /// Example usage:
-  /// ```dart
-  /// ErrorText.localizeError = (BuildContext context, FirebaseAuthException e) {
-  ///   return switch (e.code) {
-  ///     'user-not-found' => 'Please create an account first.',
-  ///     'credential-already-in-use' => 'This email is already in use.',
-  ///     _ => 'Oh no! Something went wrong.'
-  ///   }
-  /// }
-  static String Function(
-    BuildContext context,
-    FirebaseAuthException exception,
-  )? localizeError;
-
-  /// A way to customize the widget that is used across the library to show
-  /// error hints. By default a localized text is used with a color set to
-  /// [ColorScheme.error] under [MaterialApp] and
-  /// [CupertinoColors.destructiveRed] under [CupertinoApp].
-  static Widget Function(BuildContext context, String message)? builder;
-
   /// An exception that contains error details.
   /// Often this is a [FirebaseAuthException].
   final Exception exception;
@@ -91,16 +69,12 @@ class ErrorText extends StatelessWidget {
     }
 
     if (exception is FirebaseAuthException) {
-      if (localizeError != null) {
-        text = localizeError!(context, exception as FirebaseAuthException);
-      } else {
-        final e = exception as FirebaseAuthException;
-        final code = e.code;
-        final newText = localizedErrorText(code, l) ?? e.message;
+      final e = exception as FirebaseAuthException;
+      final code = e.code;
+      final newText = localizedErrorText(code, l) ?? e.message;
 
-        if (newText != null) {
-          text = newText;
-        }
+      if (newText != null) {
+        text = newText;
       }
     }