Remove Old "Show in Local Time" toggle

We don't longer use this, however, we are going to keep it hidden until we are sure that users don't want to show the calendar in US Pacific Time.

Openning this issue as a reminder to delete it in the future.

Start by searching the repository for the “Show in Local Time” toggle and references to displaying the calendar in US Pacific Time. Confirm whether the toggle is only hidden or still connected to other behavior; done means the obsolete toggle and its remaining references are removed without breaking the relevant tooling.

Written by the indexing model from the issue text.