enhance logging and fix Null pointer exception at wifi Null

src/main/java/com/safeqr/app/qrcode/controller/QRCodeTypeController.java

@@ -52,7 +52,7 @@ public class QRCodeTypeController {
     @PostMapping(value = API_URL_QRCODE_SCAN, produces = MediaType.APPLICATION_JSON_VALUE)
     public ResponseEntity<BaseScanResponse> scanQRCode(@RequestBody QRCodePayload payload,
                                                        @RequestHeader(required = false, name = HEADER_USER_ID) String userId) {
-        logger.info("Invoking scan endpoint");
+        logger.info("User Id Invoking scan endpoint: {}", userId);
         return ResponseEntity.ok(qrCodeTypeService.scanQRCode(userId, payload));
     }
 

src/main/java/com/safeqr/app/qrcode/entity/WifiEntity.java

@@ -2,6 +2,7 @@ package com.safeqr.app.qrcode.entity;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
 import jakarta.persistence.*;
 import lombok.AllArgsConstructor;
 import lombok.Data;
@@ -31,6 +32,7 @@ public class WifiEntity {
 
     private String ssid;
     private String password;
+    @JsonInclude(JsonInclude.Include.NON_EMPTY)
     private String encryption;
     private boolean hidden;
 }

src/main/java/com/safeqr/app/qrcode/service/WifiVerificationService.java

@@ -60,6 +60,11 @@ public class WifiVerificationService {
     }
 
     public String getClassification(String encryptionType) {
+        // Check if encryptionType is null
+        if (encryptionType == null) {
+            return CLASSIFY_UNSAFE;
+        }
+
         if (encryptionType.equalsIgnoreCase("WPA") ||
                 encryptionType.equalsIgnoreCase("WPA2") ||
                 encryptionType.equalsIgnoreCase("WPA3")) {