Refactor localization keys for "neighbors" terminology across multiple languages

- Updated localization keys from "neighbours" to "neighbors" in the following files:
  - app_localizations_bg.dart
  - app_localizations_de.dart
  - app_localizations_en.dart
  - app_localizations_es.dart
  - app_localizations_fr.dart
  - app_localizations_it.dart
  - app_localizations_nl.dart
  - app_localizations_pl.dart
  - app_localizations_pt.dart
  - app_localizations_ru.dart
  - app_localizations_sk.dart
  - app_localizations_sl.dart
  - app_localizations_sv.dart
  - app_localizations_uk.dart
  - app_localizations_zh.dart
- Updated corresponding ARB files to reflect the changes in keys.
- Renamed the NeighboursScreen to NeighborsScreen in the chat and repeater hub screens for consistency.

lib/screens/chat_screen.dart

@@ -497,7 +497,7 @@ class _ChatScreenState extends State<ChatScreen> {
                           path.pathBytes.isNotEmpty &&
                           directRepeater.pubkeyFirstByte ==
                               path.pathBytes.first;
-                      final isSecoundDirectRepeater =
+                      final isSecondDirectRepeater =
                           secondDirectRepeater != null &&
                           path.pathBytes.isNotEmpty &&
                           secondDirectRepeater.pubkeyFirstByte ==
@@ -510,7 +510,7 @@ class _ChatScreenState extends State<ChatScreen> {
                       Color color = Colors.grey;
                       if (isDirectRepeater) {
                         color = Colors.green;
-                      } else if (isSecoundDirectRepeater) {
+                      } else if (isSecondDirectRepeater) {
                         color = Colors.yellow;
                       } else if (isThirdDirectRepeater) {
                         color = Colors.red;