fix: replace hardcoded 'Not Connected' string with localized value

pslabVersionID was initialized and reset to the hardcoded English
string 'Not Connected' in three places in BoardStateProvider,
ignoring the user's chosen app language.

Replaced hardcoded strings with appLocalizations.notConnected so
the connection status respects the user's locale setting.
The notConnected key already exists in all supported language
ARB files.

Fixes #3392

Author: prajakta128

lib/providers/board_state_provider.dart

@@ -17,7 +17,7 @@ class BoardStateProvider extends ChangeNotifier {
   bool pslabIsConnected = false;
   bool hasPermission = false;
   late ScienceLabCommon scienceLabCommon;
-  String pslabVersionID = 'Not Connected';
+  String pslabVersionID = '';
   String pslabVersionIDV6 = 'PSLab V6';
   String pslabVersionIDV5 = 'PSLab V5';
   int pslabVersion = 0;
@@ -44,37 +44,35 @@ class BoardStateProvider extends ChangeNotifier {
 
     if (configProvider.config.autoStart) {
       if (!kIsWeb && defaultTargetPlatform == TargetPlatform.android) {
-        UsbSerial.usbEventStream?.listen(
-          (UsbEvent usbEvent) async {
-            if (usbEvent.event == UsbEvent.ACTION_USB_ATTACHED) {
-              if (_isProcessing) return;
-              _isProcessing = true;
-              if (!scienceLabCommon.isConnected() &&
-                  await attemptToConnectPSLab()) {
-                pslabIsConnected = await scienceLabCommon.openDevice();
-                await setPSLabVersionIDs();
-                await fetchFirmwareVersion();
-                _isProcessing = false;
-              }
-            } else if (usbEvent.event == UsbEvent.ACTION_USB_DETACHED &&
-                !scienceLabCommon.isWiFiConnected()) {
-              scienceLabCommon.setConnected(false);
-              pslabIsConnected = false;
-              pslabVersionID = 'Not Connected';
-              notifyListeners();
+        UsbSerial.usbEventStream?.listen((UsbEvent usbEvent) async {
+          if (usbEvent.event == UsbEvent.ACTION_USB_ATTACHED) {
+            if (_isProcessing) return;
+            _isProcessing = true;
+            if (!scienceLabCommon.isConnected() &&
+                await attemptToConnectPSLab()) {
+              pslabIsConnected = await scienceLabCommon.openDevice();
+              await setPSLabVersionIDs();
+              await fetchFirmwareVersion();
+              _isProcessing = false;
             }
-          },
-        );
+          } else if (usbEvent.event == UsbEvent.ACTION_USB_DETACHED &&
+              !scienceLabCommon.isWiFiConnected()) {
+            scienceLabCommon.setConnected(false);
+            pslabIsConnected = false;
+            pslabVersionID = appLocalizations.notConnected;
+            notifyListeners();
+          }
+        });
       }
     }
 
-    Connectivity()
-        .onConnectivityChanged
-        .listen((List<ConnectivityResult> results) {
+    Connectivity().onConnectivityChanged.listen((
+      List<ConnectivityResult> results,
+    ) {
       if (results.contains(ConnectivityResult.none)) {
         scienceLabCommon.setWiFiConnected(false);
         pslabIsConnected = false;
-        pslabVersionID = 'Not Connected';
+        pslabVersionID = appLocalizations.notConnected;
         notifyListeners();
       }
     });
@@ -100,8 +98,10 @@ class BoardStateProvider extends ChangeNotifier {
 
   Future<void> fetchFirmwareVersion() async {
     if (getIt.get<ScienceLab>().isConnected()) {
-      pslabFirmwareVersion =
-          await getIt.get<ScienceLab>().mPacketHandler.getFirmwareVersion();
+      pslabFirmwareVersion = await getIt
+          .get<ScienceLab>()
+          .mPacketHandler
+          .getFirmwareVersion();
     }
     if (pslabFirmwareVersion < 3 && pslabFirmwareVersion != 0) {
       legacyFirmwareNotifier.value = "LegacyFirmwareDetected";