Remove hidden character from front of shebang line

Found by [pycycle --verbose --source gramps]

Once corrected pycycle reports:

Project successfully transformed to AST, checking imports for cycles..

No worries, no cycles here!

gramps/plugins/test/test_imports.py

@@ -1,4 +1,4 @@
-#! /usr/bin/env python3
+#! /usr/bin/env python3
 """ Test program for import modules
 """
 #