Added method to delete system oauth2 config

common/dao-api/src/main/java/org/thingsboard/server/dao/oauth2/OAuth2Service.java

@@ -42,6 +42,8 @@ public interface OAuth2Service {
 
     void deleteTenantOAuth2ClientsParams(TenantId tenantId);
 
+    void deleteSystemOAuth2ClientsParams();
+
     boolean isOAuth2ClientRegistrationAllowed(TenantId tenantId);
 
 }

dao/src/main/java/org/thingsboard/server/dao/oauth2/OAuth2ServiceImpl.java

@@ -352,6 +352,12 @@ public class OAuth2ServiceImpl implements OAuth2Service {
         clientsParams.remove(tenantId);
     }
 
+    @Override
+    public void deleteSystemOAuth2ClientsParams() {
+        adminSettingsService.deleteAdminSettingsByKey(TenantId.SYS_TENANT_ID, OAuth2Utils.OAUTH2_CLIENT_REGISTRATIONS_PARAMS);
+        clientsParams.remove(TenantId.SYS_TENANT_ID);
+    }
+
     @Override
     public boolean isOAuth2ClientRegistrationAllowed(TenantId tenantId) {
         Tenant tenant = tenantService.findTenantById(tenantId);