feat: remove duplicate workflow lookups

Previously, anything that requested a workflow would cause a workflow
update and refresh. This changes that logic to:
1. Only init workflow API once through load of ORA block (reloaded each
time the page / ORA MFE load).
2. On load, update workflow.
3. Calls for workflow info reference cached workflow.
4. Try to update workflow when none found.

Note we can still  manually refresh workflow info with either
get_workflow_info or update_workflow_status.

openassessment/xblock/apis/ora_data_accessor.py

@@ -27,7 +27,7 @@ def submission_data(self):
 
     @property
     def workflow_data(self):
-        return WorkflowAPI(self._block)
+        return self._block.workflow_data
 
     @property
     def grades_data(self):

openassessment/xblock/apis/workflow_api.py

@@ -10,13 +10,28 @@ class WorkflowAPI:
     def __init__(self, block):
         self._block = block
         self.grades = self._block.grades_data
+        self._workflow = self._block.get_workflow_info()
 
     def get_workflow_info(self, submission_uuid=None):
-        return self._block.get_workflow_info(submission_uuid)
+        """
+        Update workflow info and return workflow for the submission.
+
+        NOTE - calls workflow update
+        """
+        self._workflow = self._block.get_workflow_info(submission_uuid)
+        return self._workflow
 
     @property
     def workflow(self):
-        return self.get_workflow_info()
+        """
+        Getter for workflow, used to keep us from updating workflow every time
+        we ask for info.
+
+        NOTE - when there isn't a workflow, this will try to refresh workflow.
+        """
+        if not self._workflow:
+            return self.get_workflow_info()
+        return self._workflow
 
     @property
     def has_workflow(self):
@@ -34,6 +49,11 @@ def has_status(self):
     def status_details(self):
         return self.workflow.get("status_details", {})
 
+    @property
+    def status(self):
+        if self.workflow:
+            return self.workflow.get("status")
+
     def has_reached_given_step(self, requested_step, current_workflow_step=None):
         """
         Helper to determine if are far enough through a workflow to request data for a step.
@@ -102,10 +122,6 @@ def submission_uuid(self):
     def workflow_requirements(self):
         return self._block.workflow_requirements()
 
-    @property
-    def status(self):
-        return self.workflow.get("status")
-
     @property
     def has_received_grade(self):
         return bool(self.workflow.get('score'))
@@ -120,6 +136,9 @@ def get_course_workflow_settings(self):
         return self._block.get_course_workflow_settings()
 
     def update_workflow_status(self, submission_uuid=None):
+        """
+        NOTE - calls workflow update.
+        """
         self._block.update_workflow_status(submission_uuid)
 
     def create_workflow(self, submission_uuid):

openassessment/xblock/openassessmentblock.py

@@ -293,9 +293,14 @@ class OpenAssessmentBlock(
     def config_data(self):
         return ORAConfigAPI(self)
 
+    _workflow_data = None
+
     @property
     def workflow_data(self):
-        return WorkflowAPI(self)
+        # Initialize Workflow API only once
+        if not self._workflow_data:
+            self._workflow_data = WorkflowAPI(self)
+        return self._workflow_data
 
     @property
     def submission_data(self):