fix(flutter): drop redundant const in nested const contexts

Making the outer FabledSwordTheme(...) and HomeData(...) constructors
const made every inner const redundant — Dart's analyzer fires
unnecessary_const for each. Strip the inner consts so the outer
context owns the const inference.

flutter_client/lib/theme/theme_extension.dart

@@ -45,9 +45,9 @@ class FabledSwordTheme extends ThemeExtension<FabledSwordTheme> {
         warning: FabledSwordTokens.warning,
         error: FabledSwordTokens.error,
         info: FabledSwordTokens.info,
-        display: const TextStyle(fontFamily: FabledSwordTokens.fontDisplay),
-        body: const TextStyle(fontFamily: FabledSwordTokens.fontBody),
-        mono: const TextStyle(fontFamily: FabledSwordTokens.fontMono),
+        display: TextStyle(fontFamily: FabledSwordTokens.fontDisplay),
+        body: TextStyle(fontFamily: FabledSwordTokens.fontBody),
+        mono: TextStyle(fontFamily: FabledSwordTokens.fontMono),
       );
 
   @override