Revert PR #278 which added additional length checks to bulk SMS sends

[whabanks]

Summary | Résumé

Reverts #278
We encountered a couple issues where SMS limit checking that was a part of this PR was applying to bulk emails when it should only be applicable to bulk SMS.

Related Issues | Cartes liées

#292
cds-snc/notification-admin#1822
cds-snc/notification-api#2164

Test instructions | Instructions pour tester la modification

Release Instructions | Instructions pour le déploiement

After this PR, cds-snc/notification-admin#1822 and cds-snc/notification-api#2164 are merged, we need to:

1. Bump and tag utils.
2. Bump the utils version in Admin and API.

Reviewer checklist | Liste de vérification du réviseur

• This PR does not break existing functionality.
• This PR does not violate GCNotify's privacy policies.
• This PR does not raise new security concerns. Refer to our GC Notify Risk Register document on our Google drive.
• This PR does not significantly alter performance.
• Additional required documentation resulting of these changes is covered (such as the README, setup instructions, a related ADR or the technical documentation).

⚠ If boxes cannot be checked off before merging the PR, they should be moved to the "Release Instructions" section with appropriate steps required to verify before release. For example, changes to celery code may require tests on staging to verify that performance has not been affected.