[REF] all: pass pre-commit on the whole repo

Needed for the lint job of the CI to go green. Mostly automatic hook
fixes (black, isort, prettier, pyupgrade, autoflake, whitespace). By hand:

- flake8: two unused imports, an ambiguous variable name `l`.
- pylint-odoo mandatory: manifest keys equal to their default value
  (installable, application, data, external_dependencies).
- end-of-file-fixer skips *.patch too, like trailing-whitespace: the
  upstream patches stay as git format-patch wrote them.

No behaviour change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

portal_event_registration/controllers/portal.py

@@ -1,7 +1,9 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
-from odoo import _, http
-from odoo.exceptions import AccessError, MissingError
+from odoo import _
+from odoo import http
+from odoo.exceptions import AccessError
+from odoo.exceptions import MissingError
 from odoo.http import request
 
 from odoo.addons.portal.controllers.portal import CustomerPortal