Drupal: tech debt cleanup from Support services phone number update

[jilladams]

Description

In #19836, we swapped phone number fields: added a new , and hid the old. We now want to fully remove the old phone number field.

Acceptance criteria

• Remove field_phone_number from Support Service
• Build Drupal and FE in a tugboat, and verify that both compile, and front-end presentation is still correct before merge