update sams_hub.py _conext_processor to pass test_session_language_used

sams_classes/sams_hub.py

-from flask import Flask, request
+from flask import Flask, request, session
 from .exceptions import (
   ManifestDefaultLanguageMissing
   , DefaultLanguageDictMissing
@@ -57,8 +57,8 @@ class SAMSHub:
   
   def _context_processor(self):
     return {
-      'app_lang': self.app(
-        request.blueprint).lang(self._config['default_language']
+      'app_lang': self.app(request.blueprint).lang(
+        session.get('language', self._config['default_language'])
       )
     }