[BUG] [Server: Python] Missed space for Basic auth in python-flask/controller_test.mustache

Created by: pavlot

Description

https://github.com/OpenAPITools/openapi-generator/blob/4e352cb28261b68fe87adbd64db77565a4ffcd90/modules/openapi-generator/src/main/resources/python-flask/controller_test.mustache#L36

Missed " " after word Basic in construction {{#isBasicBasic}}'Authorization': 'BasicZm9vOmJhcg==',{{/isBasicBasic}}