fix(core): middleware is not executed for root route when global prefix is set

[kamilmysliwiec]

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: #11572

What is the new behavior?

Based off #12179

Does this PR introduce a breaking change?

• Yes
• No

Other information

[coveralls]

Pull Request Test Coverage Report for Build 7adabfa0-ed39-40ba-9e86-028b02c6c50f

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 92.146%

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Totals
Change from base Build 68ba9650-c952-423f-be1b-e55bad701ad4:	0.0%
Covered Lines:	6734
Relevant Lines:	7308

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💛 - Coveralls

[B4nan]

I'll have to check this myself, but I already heard from two of our users that this is not fixing the actual problem, at least not for the MikroORM integration.