Mitra Profil: drop handle subtitle on WA/TG rows

User feedback — the wa.me/... and t.me/... subtitles under "Chat
WhatsApp Kami" / "Chat Telegram Kami" leaked the raw URL into the UI.
Just the label now, matching how typical "contact us" menu entries
read. Tap still launches the deeplink from backend config.

Drop the unused `SupportHandle.displayHandle` getter that produced the
scheme-stripped subtitle — no other call site.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mitra_app/lib/features/profile/support_handles_provider.dart

@@ -11,16 +11,6 @@ class SupportHandle {
         label: json['label'] as String? ?? '',
         deeplink: json['deeplink'] as String? ?? '',
       );
-
-  /// Display form for the menu subtitle: strip the URL scheme so
-  /// "https://wa.me/6285173310010" → "wa.me/6285173310010" and
-  /// "https://t.me/halobestie" → "t.me/halobestie". Falls back to the
-  /// raw deeplink when there's no scheme to strip.
-  String get displayHandle {
-    if (deeplink.isEmpty) return '';
-    final stripped = deeplink.replaceFirst(RegExp(r'^https?://'), '');
-    return stripped;
-  }
 }
 
 class SupportHandles {