fix: STS Token API Response

Author: pratapipatelbcone

src/main/java/org/eclipse/tractusx/managedidentitywallets/controller/SecureTokenController.java

@@ -139,7 +139,7 @@ private ResponseEntity<StsTokenResponse> processTokenRequest(SecureTokenRequest
                 .token(responseJwt.serialize())
                 .expiresAt(responseJwt.getJWTClaimsSet().getExpirationTime().getTime())
                 .build();
-        return ResponseEntity.status(HttpStatus.CREATED).body(response);
+        return ResponseEntity.status(HttpStatus.OK).body(response);
     }
 
     @ExceptionHandler({ UnsupportedGrantTypeException.class, InvalidSecureTokenRequestException.class, UnknownBusinessPartnerNumberException.class, InvalidIdpTokenResponseException.class })

src/main/java/org/eclipse/tractusx/managedidentitywallets/domain/StsTokenResponse.java

@@ -21,6 +21,7 @@
 
 package org.eclipse.tractusx.managedidentitywallets.domain;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Getter;
@@ -33,6 +34,9 @@
 @NoArgsConstructor
 @AllArgsConstructor
 public class StsTokenResponse {
+
+    @JsonProperty("access_token")
     private String token;
+
     private long expiresAt;
 }