fix CapabilityEngine

fix CapabilityEngine to actually load the capability execution it's executing and then properly release the engine after completion

shared/workspaces/workspaces/capability/services/capability_engine.py

@@ -22,17 +22,26 @@ class CapabilityEngine(CapabilityEngineIF):
     ):
         self.capability_info = capability_info
         self.workflow_service = workflow_service
+        self.execution = None
 
-    def execute(self, execution: CapabilityExecutionIF):
+    def load_engine(self, execution: CapabilityExecutionIF):
+        """
+        Load capability execution of interest into capability engine for access and execution
+        :param execution: execution to be executed by this engine
+        :return:
+        """
+        self.execution = execution
+
+    def execute(self):
         """
         Communicate with workflow service and send a request to run a workflow with given settings
 
         :param execution:
         """
-        step_sequence = CapabilitySequence.from_str(execution.steps)
+        step_sequence = CapabilitySequence.from_str(self.execution.steps)
         # Grab value of current step (workflow name)
-        cur_step = step_sequence[int(execution.current_step)]
-        cur_step.execute(self, execution)
+        cur_step = step_sequence[int(self.execution.current_step)]
+        cur_step.execute(self, self.execution)
 
     def submit_workflow_request(
         self, execution_id: int, workflow_name: str, workflow_args: dict, files: List[AbstractFile]