refactor: enhance localization support in chat and voice input features

- Integrated localization for various dialog messages and UI elements in the chat and voice input components.
- Updated the confirmation dialog to utilize localized strings for delete messages, improving user experience across different languages.
- Enhanced voice input sheet to reflect localized text for status updates, action buttons, and prompts, ensuring consistency in user interactions.
- Improved the file attachment widget to display the attachment label in a localized manner, enhancing accessibility for users in different regions.
- Streamlined localization management by centralizing string retrieval, promoting maintainability and clarity in the codebase.

lib/features/chat/widgets/file_attachment_widget.dart

@@ -231,7 +231,7 @@ class MessageAttachmentPreview extends StatelessWidget {
                     ),
                     const SizedBox(width: Spacing.xs),
                     Text(
-                      'Attachment',
+                      AppLocalizations.of(context)!.attachmentLabel,
                       style: TextStyle(
                         color: context.conduitTheme.textPrimary.withValues(
                           alpha: 0.8,