Map ‘pending’ status to ‘sending’
Map ‘pending’ status to ‘sending’

For some reason we are getting pending back as a status from one of
our text message providers.

Because this is unrecognised by the admin app it shows up in the list of
messages as the raw status, styled like an error.

This commit maps it to sending instead, because the user doesn’t need to
know or care about the difference.

alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin