Fix/rmq microservice fanout bind

[slon2015]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

Issue Number: #15746

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

[coveralls]

Pull Request Test Coverage Report for Build 0204bf64-9742-4092-b778-345b881741c6

Details

• 12 of 14 (85.71%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 88.836%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/microservices/client/client-rmq.ts	6	7	85.71%
packages/microservices/server/server-rmq.ts	6	7	85.71%

Totals
Change from base Build bdf8f055-4cf2-40ae-a7a2-1f06f79197e6:	0.1%
Covered Lines:	7289
Relevant Lines:	8205

---

💛 - Coveralls

[kamilmysliwiec]

Would you like to add an integration test for this change?

[slon2015]

Integration test added

[slon2015]

@kamilmysliwiec do you have any other feedback?