Summary

Now that the DB supports this (T412962), we should add a checkbox to the global blocking interfaces that supports marking a global block as disabling email.

Background

• See T401293: Global blocking should have an option to disable sending email for more detail
  • However, this task specifically is focusing on adding the checkboxes to the relevant interfaces so that stewards can use the feature.
    • The checkbox should be disabled by default, but use the value from an existing block if modifying a global block

Acceptance criteria

• The global blocking interfaces have this checkbox