remove(statcan.alpha.canada.ca): remove unneeded registrations.

[justbert]

Summary | Résumé

No longer needed since these sites are being taken down.

[patheard]

@justbert could you take a look at the duplicated PR I've created here to apply your change:

• https://github.com/cds-snc/dns/pull/363

If all looks as you expect, I'll get it merged for you!