added validation for app name length when creating an app (Front end part)

components/application-mgt/io.entgra.application.mgt.publisher.api/src/main/java/io/entgra/application/mgt/publisher/api/services/ApplicationManagementPublisherAPI.java

@@ -747,6 +747,9 @@ public interface ApplicationManagementPublisherAPI {
                     @ApiResponse(
                             code = 409,
                             message = "CONFLICT. \n Application exists"),
+                    @ApiResponse(
+                            code = 411,
+                            message = "LENGTH_REQUIRED. \n Invalid application name length"),
                     @ApiResponse(
                             code = 400,
                             message = "Bad Request. \n Found invalid device type with the request."),

components/application-mgt/io.entgra.application.mgt.publisher.api/src/main/java/io/entgra/application/mgt/publisher/api/services/impl/ApplicationManagementPublisherAPIImpl.java

@@ -373,11 +373,16 @@ public class ApplicationManagementPublisherAPIImpl implements ApplicationManagem
                 log.error(msg);
                 return Response.status(Response.Status.BAD_REQUEST).build();
             }
+            if(appName.length()>20){
+                String msg = "Invalid app name, maximum length of the application name should be 20 characters.";
+                log.error(msg);
+                return Response.status(Response.Status.LENGTH_REQUIRED).build();
+            }
             ApplicationManager applicationManager = APIUtil.getApplicationManager();
             if (applicationManager.isExistingAppName(appName, deviceType)) {
                 return Response.status(Response.Status.CONFLICT).build();
             }
-            return Response.status(Response.Status.OK).build();
+                return Response.status(Response.Status.OK).build();
         } catch (BadRequestException e) {
             log.error("Found invalid device type to check application existence.", e);
             return Response.status(Response.Status.BAD_REQUEST).build();