[feat] Make report annotations compatible with store speedup

By moving the the additon of annotations from the add_report method to
the add_report_context method (and removing the flush from the handler
function), the same session flushing strategy was restored.

web/server/codechecker_server/api/mass_store_run.py

@@ -828,6 +828,10 @@ def __add_report_context(self, session, file_path_to_id):
                         macro.message, file_path_to_id[macro.file.path],
                         db_report.id, data_type))
 
+                if report.annotations:
+                    self.__validate_and_add_report_annotations(
+                        session, db_report.id, report.annotations)
+
             session.flush()
 
         except Exception as ex:
@@ -982,9 +986,6 @@ def get_missing_file_ids(report: Report) -> List[str]:
                 rs_from_source, detection_status, detected_at,
                 run_history_time, analysis_info, analyzer_name, fixed_at)
 
-            if report.annotations:
-                self.__validate_and_add_report_annotations(
-                    session, report_id, report.annotations)
             self.__new_report_hashes[report.report_hash] = \
                 rs_from_source.status
             self.__already_added_report_hashes.add(report_path_hash)
@@ -1038,8 +1039,6 @@ def __validate_and_add_report_annotations(
                     f"'{ALLOWED_ANNOTATIONS[key]['display']}'."
                 )
 
-        session.flush()
-
     def __store_reports(
         self,
         session: DBSession,