TMSS-195: ignore empty default constraint

SAS/TMSS/backend/services/scheduling/lib/constraints/template_constraints_v1.py

@@ -295,7 +295,7 @@ def can_run_anywhere_within_timewindow_with_sky_constraints(scheduling_unit: mod
                                 else:
                                     logger.info('min_target_elevation=%s constraint is not met at timestamp=%s' % (min_elevation.rad, timestamps[i]))
                                 return False
-                if 'transit_offset' in constraints['sky'] and task['specifications_template'] == 'target observation':
+                if 'transit_offset' in constraints['sky'] and 'from' in constraints['sky']['transit_offset'] and task['specifications_template'] == 'target observation':
                     # Check constraint on tile beam for HBA only:
                     if task['specifications_doc']['antenna_set'].startswith('HBA'):
                         # since the constraint only applies to the middle of the obs, consider its duration
@@ -323,7 +323,7 @@ def can_run_anywhere_within_timewindow_with_sky_constraints(scheduling_unit: mod
                                     return False
 
             if 'SAPs' in task['specifications_doc']:
-                if 'transit_offset' in constraints['sky'] and task['specifications_template'] == 'target observation':
+                if 'transit_offset' in constraints['sky']  and 'from' in constraints['sky']['transit_offset'] and task['specifications_template'] == 'target observation':
                     # Check constraint on SAPs for LBA only:
                     if task['specifications_doc']['antenna_set'].startswith('LBA'):
                         # since the constraint only applies to the middle of the obs, consider its duration