fix(service): remove doctor check from cache.migrations_check

[Panaetius]

closes #3578

/deploy #persist

[RenkuBot]

You can access the deployment of this PR at https://renku-ci-rp-3597.dev.renku.ch

[coveralls]

Pull Request Test Coverage Report for Build 5941092628

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 15 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-0.04%) to 85.668%

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Files with Coverage Reduction	New Missed Lines	%
renku/core/dataset/providers/dataverse.py	1	64.76%
renku/ui/cli/init.py	1	96.9%
renku/ui/service/cache/models/file.py	1	93.15%
renku/command/rollback.py	2	78.7%
renku/ui/service/jobs/cleanup.py	2	80.65%
renku/ui/cli/service.py	3	66.67%
renku/command/checks/datasets.py	5	81.65%

Totals
Change from base Build 5931488864:	-0.04%
Covered Lines:	25828
Relevant Lines:	30149

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💛 - Coveralls