fix(microservices): ensure all redis and amqp client closes properly

[yatin166]

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?

Redis and AMQP close connection method is asynchronous, in the current behaviour, connection were not properly closed for pub/sub or channel/client for clients due to missing async/await.

Issue Number: N/A

What is the new behavior?

Added async/await when close() is called for pub/sub or channel/client in client-redis and client-rmq respectively, so that all the connections are properly closed.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[coveralls]

Pull Request Test Coverage Report for Build f0eb5fd0-aeb2-45c0-9868-b529fc3b37d8

Details

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 88.923%

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Totals
Change from base Build c99d332b-8204-48ec-bc18-15971298dd6e:	0.0%
Covered Lines:	7177
Relevant Lines:	8071

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💛 - Coveralls

[kamilmysliwiec]

LGTM