Core: Add restricted_dumps helper (#5117)

* Add pickling helper that check unpicklability

* Add test condition and generation error handling

* Fix incorrect call and make imports consistent

* Fix newline padding

* Change PicklingError to directly caused by UnpicklingError

Co-authored-by: Doug Hoskisson <beauxq@users.noreply.github.com>

* Revert to `pickle.dumps` for decompressed multidata

* Fix import order

* Restore pickle import in main

* Re-add for multidata in Main

* Remove multisave checks

* Update MultiServer.py

* Update customserver.py

---------

Co-authored-by: Doug Hoskisson <beauxq@users.noreply.github.com>
Co-authored-by: NewSoupVi <57900059+NewSoupVi@users.noreply.github.com>

WebHostLib/api/generate.py

@@ -1,11 +1,11 @@
 import json
-import pickle
 from uuid import UUID
 
 from flask import request, session, url_for
 from markupsafe import Markup
 from pony.orm import commit
 
+from Utils import restricted_dumps
 from WebHostLib import app
 from WebHostLib.check import get_yaml_data, roll_options
 from WebHostLib.generate import get_meta
@@ -56,7 +56,7 @@ def generate_api():
                     "detail": results}, 400
         else:
             gen = Generation(
-                options=pickle.dumps({name: vars(options) for name, options in gen_options.items()}),
+                options=restricted_dumps({name: vars(options) for name, options in gen_options.items()}),
                 # convert to json compatible
                 meta=json.dumps(meta), state=STATE_QUEUED,
                 owner=session["_id"])