fix(fakedata): remove undefined structure reference from users

Fixing bug after Merge branch '77-enchance-default-structures-generation' into 'dev'

app/imports/startup/server/db-initialize/fakeData.json

@@ -4,14 +4,12 @@
       "email": "admin@ac-dijon.fr",
       "password": "changeme",
       "role": "admin",
-      "structure": "EviKfwAnFtcjEWFdz",
       "firstName": "Jean",
       "lastName": "Dupont"
     },
     {
       "email": "eole@ac-dijon.fr",
       "password": "changeme",
-      "structure": "EviKfwAnFtcjEWFdz",
       "firstName": "Guy",
       "lastName": "Durand"
     }