[FEATURE]: Support system tasks other than the SubWorkflow task as parent of a Sub Workflow

## Describe the Feature Request

I have been working on an custom system task that launches multiple SubWorkflows in a loop. However, I found there were a number of places with logic hardcoded to taskType that prevented this working.

There are hardcoded references to SUB_WORKFLOW in the following places methods:

1. `WorkflowExecutorOps.executeSubworkflowTaskAndSyncData` called from `updateParentWorkflowTask`

```
@VisibleForTesting
void updateParentWorkflowTask(WorkflowModel subWorkflow) {
TaskModel subWorkflowTask =
executionDAOFacade.getTaskModel(subWorkflow.getParentWorkflowTaskId());
executeSubworkflowTaskAndSyncData(subWorkflow, subWorkflowTask);
executionDAOFacade.updateTask(subWorkflowTask);
}

private void executeSubworkflowTaskAndSyncData(
WorkflowModel subWorkflow, TaskModel subWorkflowTask) {
WorkflowSystemTask subWorkflowSystemTask =
systemTaskRegistry.get(TaskType.TASK_TYPE_SUB_WORKFLOW);
subWorkflowSystemTask.execute(subWorkflow, subWorkflowTask, this);
}

```

2. `WorkflowExecutorOps.findChangedSubWorkflowTask`
- note the initial filtering here might be a bug assuming DYNAMIC_TASK could also run a SubWorkflow task

```
if (workflowDef.containsType(TaskType.TASK_TYPE_SUB_WORKFLOW)
|| workflow.getWorkflowDefinition()
.containsType(TaskType.TASK_TYPE_FORK_JOIN_DYNAMIC)) {
return workflow.getTasks().stream()
.filter(
t ->
t.getTaskType().equals(TaskType.TASK_TYPE_SUB_WORKFLOW)
&& t.isSubworkflowChanged()
&& !t.isRetried())
.findFirst();
}
```

3. `WorkflowExecutorOps.rerunWF` (line 1669 & 1772)

4. `WorkflowExecutorOps.findLastFailedSubWorkflowIfAny` (line 413)

5. `WorkflowRepairService.verifyAndRepairTask` (line 154)

## Describe Preferred Solution

1. Change the `WorkflowExecutorOps.executeSubworkflowTaskAndSyncData` to pass`subWorkflowTask.getTaskType()` to the `systemTaskRegistry`

```
private void executeSubworkflowTaskAndSyncData(
WorkflowModel subWorkflow, TaskModel subWorkflowTask) {
WorkflowSystemTask subWorkflowSystemTask =
systemTaskRegistry.get(subWorkflowTask.getTaskType()); // replace hard coding here
subWorkflowSystemTask.execute(subWorkflow, subWorkflowTask, this);
}
```

2. And the following method to `WorkflowSystemTask` interface and override to return true in `SubWorkflow` class:

```
public boolean isSubWorkflowParent() { return false; }
```

Add additional method to `SystemTaskRegistry`

```
public boolean isSubWorkflowParent(String taskType) {
return get(taskType).isSubWorkflowParent();
}
```

3. Replace logic that explicitly checks for hardcoding with checks on the SystemRegistry

``
systemTaskRegistry.isSubWorkflowParent(t.getTaskType())

```

## Describe Alternatives

I am not aware of other viable options, as the task type still needs to be unique