Fix concurrent starting the next group (#1853)

when in StartNextGroupRolloutGroupSuccessAction#startNextGroup:
    1. start all scheduled actions
    2. if started are > 0 -> RUNNING, otherwise -> FINISHED (if not dynamic rollout)

what could possibly happen is that at same time:
    * because of a success condition met the JpaRolloutsExecutor triggers start the group
    * user triggers start of the next group (via RolloutsManagement#triggerNextGroup)

then it could:
    * the 'first' one succeeds to start next group
    * the second attempts to start it (JpaRolloutsExecutor found the previous had met the success condition or trigger next found it SCHEDULED and next to run)
    * the second finds no scheduled actions (just running) and decides there are no actions. So, it assumes (wrongly) no actions in group - and set it as FINISHED

This way we could have FINISHED group with still running actions

Signed-off-by: Marinov Avgustin <Avgustin.Marinov@bosch.com>

hawkbit-repository/hawkbit-repository-jpa/src/test/java/org/eclipse/hawkbit/repository/jpa/management/RolloutManagementTest.java

@@ -374,15 +374,12 @@ class RolloutManagementTest extends AbstractJpaIntegrationTest {
                 successCondition, errorCondition);
 
         finishActionAndDeleteTargetsOfFirstRunningGroup(createdRollout);
-
         checkSecondGroupStatusIsRunning(createdRollout);
 
         finishActionAndDeleteTargetsOfSecondRunningGroup(createdRollout);
-
         deleteAllTargetsFromThirdGroup(createdRollout);
-
+        rolloutHandler.handleAll(); // one more time to finish the second group
         verifyRolloutAndAllGroupsAreFinished(createdRollout);
-
     }
 
     @Step("Finish three actions of the rollout group and delete two targets")