Use the default TTL for Review app DNS records

What does this MR do and why?

Previously we were hosting DNS with Route 53 and a TTL of 10s was allowed. Since we've migrated gitlab-review.app to Cloudflare, it seems to require that TTLs are between 30 and 86400 seconds, or 1 for automatic. Removing the annotation should set the TTL to 1.

This will avoid getting errors such as:

2023-11-30 14:01:05.082 CET
time="2023-11-30T13:01:05Z" level=info msg="Changing record." action=UPDATE record=gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=10 type=A zone=1e227cc1f9b27b040d9a252482f36b62
2023-11-30 14:01:05.322 CET
time="2023-11-30T13:01:05Z" level=error msg="failed to update record: TTL must be between 30 and 86400 seconds, or 1 for Automatic. (9021)" action=UPDATE record=gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=10 type=A zone=1e227cc1f9b27b040d9a252482f36b62
2023-11-30 14:03:16.321 CET
time="2023-11-30T13:03:16Z" level=info msg="Changing record." action=UPDATE record=gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=1 type=TXT zone=1e227cc1f9b27b040d9a252482f36b62
2023-11-30 14:03:16.573 CET
time="2023-11-30T13:03:16Z" level=info msg="Changing record." action=UPDATE record=a-gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=1 type=TXT zone=1e227cc1f9b27b040d9a252482f36b62
2023-11-30 14:04:05.658 CET
time="2023-11-30T13:04:05Z" level=info msg="Changing record." action=UPDATE record=gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=10 type=A zone=1e227cc1f9b27b040d9a252482f36b62
2023-11-30 14:04:05.871 CET
time="2023-11-30T13:04:05Z" level=error msg="failed to update record: TTL must be between 30 and 86400 seconds, or 1 for Automatic. (9021)" action=UPDATE record=gitlab-review-430109-fro-22f76u.gitlab-review.app ttl=10 type=A zone=1e227cc1f9b27b040d9a252482f36b62

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