Concurrency policy not running if set to one

SUMMARY

If you were to set the concurrency policy of an action to be 1 then it does not run any actions. I believe the following piece of code is responsible:

https://github.com/StackStorm/st2/blob/d374b92f0dbf6b26c5dfdcffd594ecbd0800d635/st2actions/st2actions/policies/concurrency.py#L53C12-L53C34

        count = scheduled + running

        # Mark the execution as scheduled if threshold is not reached or delayed otherwise.
        if count < self.threshold:
            LOG.debug(
                "There are %s instances of %s in scheduled or running status. "
                "Threshold of %s is not reached. Action execution will be scheduled.",
                count,
                target.action,
                self._policy_ref,
            )
            status = action_constants.LIVEACTION_STATUS_REQUESTED
        else:
            action = "delayed" if self.policy_action == "delay" else "canceled"
            LOG.debug(
                "There are %s instances of %s in scheduled or running status. "
                "Threshold of %s is reached. Action execution will be %s.",
                count,
                target.action,
                self._policy_ref,
                action,
            )
            status = self._get_status_for_policy_action(action=self.policy_action)

I think this should be changed to:

        count = scheduled + running

        # Mark the execution as scheduled if threshold is not reached or delayed otherwise.
        if count <= self.threshold:
            LOG.debug(
                "There are %s instances of %s in scheduled or running status. "
                "Threshold of %s is not reached. Action execution will be scheduled.",
                count,
                target.action,
                self._policy_ref,
            )
            status = action_constants.LIVEACTION_STATUS_REQUESTED
        else:
            action = "delayed" if self.policy_action == "delay" else "canceled"
            LOG.debug(
                "There are %s instances of %s in scheduled or running status. "
                "Threshold of %s is reached. Action execution will be %s.",
                count,
                target.action,
                self._policy_ref,
                action,
            )
            status = self._get_status_for_policy_action(action=self.policy_action)

and a unit test should be added.

Steps to reproduce the problem

Set the policy to be 1 for a specific action in stackstorm, and try to run the action using something like with items.

Expected Results

One action running at a time.

Actual Results

No actions run and they stay in the policy_action state.

Start in st2actions/st2actions/policies/concurrency.py at the threshold comparison linked in the issue. Add a unit test covering a concurrency policy of 1, then verify that one action runs at a time and additional executions receive the configured policy action instead of all remaining stuck.