Revise regular expression and re.sub() command so exactly one space i…

…s accepted between a UBKG-recognized soft assay type and square brackets containing values not validated.

src/schema/schema_validators.py

@@ -64,7 +64,7 @@ def validate_application_header_before_entity_create(normalized_entity_type, req
 def validate_recognized_dataset_type(property_key, normalized_entity_type, request, existing_data_dict, new_data_dict):
     # If the proposed Dataset dataset_type ends with something in square brackets, anything inside
     # those square brackets are acceptable at the end of the string.  Simply validate the start.
-    proposed_dataset_type_prefix = re.sub(pattern='[ ]*\[.*]$', repl='', string=new_data_dict['dataset_type'])
+    proposed_dataset_type_prefix = re.sub(pattern='(\S)\s\[.*\]$', repl=r'\1', string=new_data_dict['dataset_type'])
     target_list = schema_manager.get_dataset_type_valueset_list()
 
     if proposed_dataset_type_prefix not in target_list: