This fix stabilizes an internal email-related test by keeping generated access links consistent during the test run. It helps prevent false test failures in automated checks, supporting smoother maintenance and release validation without changing user-facing behavior.

Due to the changes in https://github.com/odoo/odoo/pull/153265 , the access url for the test record
changed between the setup and the mails being sent.
By patching the token generation function we ensure that the token stays
the same during the lifetime of the test.

Runbot-Error: 98029, 98030

The Gantt view now supports translation for date range terms, so users can see these labels in their preferred language. This improves usability for multilingual teams without changing existing workflows.