Fix deprecated note for service bus attributes

[joaopgrassi]

Changes

While working on the messaging migration guide, I noticed the deprecated attribute messaging.servicebus.destination.subscription_name mentions the wrong attribute that replaces it.

Merge requirement checklist

• [x] CONTRIBUTING.md guidelines followed.
• [x] Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• [ ] schema-next.yaml updated with changes to existing conventions.

[joaopgrassi]

CC @lmolkova