Improvements for case null returned from repository

application/src/main/java/org/thingsboard/server/service/security/auth/oauth2/AbstractOAuth2ClientMapper.java

@@ -31,6 +31,7 @@ import org.thingsboard.server.common.data.Tenant;
 import org.thingsboard.server.common.data.User;
 import org.thingsboard.server.common.data.id.CustomerId;
 import org.thingsboard.server.common.data.id.DashboardId;
+import org.thingsboard.server.common.data.id.IdBased;
 import org.thingsboard.server.common.data.id.TenantId;
 import org.thingsboard.server.common.data.oauth2.OAuth2MapperConfig;
 import org.thingsboard.server.common.data.oauth2.OAuth2Registration;
@@ -205,7 +206,7 @@ public abstract class AbstractOAuth2ClientMapper {
     }
 
     private Optional<DashboardId> getDashboardId(TenantId tenantId, String dashboardName) {
-        return Optional.of(dashboardService.findFirstDashboardInfoByTenantIdAndName(tenantId, dashboardName).getId());
+        return Optional.ofNullable(dashboardService.findFirstDashboardInfoByTenantIdAndName(tenantId, dashboardName)).map(IdBased::getId);
     }
 
     private Optional<DashboardId> getDashboardId(TenantId tenantId, CustomerId customerId, String dashboardName) {