Tests: `LayerTest.test_dynamic_http_port` is flaky

[amotl]

Problem

Because some spots of the test suite are flaky, after recent refactorings, we are now receiving this

tests/testing/test_layer.py:315: 

crate_layer = <crate.testing.layer.CrateLayer object at 0x103b1fac0>

    def num_cluster_nodes(crate_layer):
>       sql_uri = crate_layer.crate_servers[0] + "/_sql"
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E       IndexError: list index out of range

-- https://github.com/crate/crate-python/actions/runs/21165186634/job/60907808795?pr=771#step:6:162

Details

Apparently, the problem is mostly happening on macOS?

[amotl]

Duplicate of GH-404. Closing.

[amotl]

Another spot.

-- https://github.com/crate/crate-python/actions/runs/21772980352/job/62824036646#step:6:108