Fix test ordering/parallelisation in HAPI tests (test-client) to work with JUnit 5.10.4 or later

We would like to upgrade JUnit to the latest release (currently `6.0.1`) for all modules in `hiero-consensus-node`.

This is blocked since July 2024 as a change (fix?) in JUnit causes HAPI test execution to fail in many cases. This is likely related to test ordering on which some of the tests rely.

Initial analysis: https://github.com/hiero-ledger/hiero-consensus-node/pull/17125#issuecomment-2633158225

To reproduce the issue, update the version of JUnit here:
https://github.com/hiero-ledger/hiero-consensus-node/blob/main/hiero-dependency-versions/build.gradle.kts#L20