Sumit Kumar

Add check for closed workflow in workflow repair service

2

Pull Request type ---- - [x] Bugfix - [ ] Feature - [ ] Refactoring (no functional changes, no api changes) - [ ] Build related changes (Please run `./gradlew...

**Describe the bug** Workflow repair logic fails with NPE when workflow information is not present in data store. ``` java.lang.NullPointerException: null at com.netflix.conductor.core.reconciliation.WorkflowRepairService.verifyAndRepairWorkflowTasks(WorkflowRepairService.java:105) ~[conductor-core-3.11.3.jar:3.11.3] at com.netflix.conductor.core.reconciliation.WorkflowSweeper.sweep(WorkflowSweeper.java:74) ~[conductor-core-3.11.3.jar:3.11.3] at com.netflix.conductor.core.reconciliation.WorkflowSweeper.sweepAsync(WorkflowSweeper.java:62) ~[conductor-core-3.11.3.jar:3.11.3]...