fix(tests): Fix flakiness of test

[iambriccardo]

This PR fixes a flakiness in env dependent tests for which there was a race condition where tests would interfere with the same environment variables, causing invariants to be violated for individual tests and thus resulting in a failure.

With this fix, we are now locking those tests, this way we guarantee mutual exclusion for the whole execution.

[coveralls]

Pull Request Test Coverage Report for Build 19957305209

Details

• 7 of 7 (100.0%) changed or added relevant lines in 1 file are covered.
• 24 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.04%) to 82.425%

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Files with Coverage Reduction	New Missed Lines	%
etl-postgres/src/tokio/test_utils.rs	4	86.47%
etl/src/replication/client.rs	20	85.55%

Totals
Change from base Build 19929298247:	0.04%
Covered Lines:	16546
Relevant Lines:	20074

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💛 - Coveralls