DataPlaneHttpToHttpIntegrationTests are flaky

[ndr-brt]

Bug Report

Describe the Bug

DataPlaneHttpToHttpIntegrationTests are flaky:
https://github.com/eclipse-dataspaceconnector/DataSpaceConnector/runs/7893124089

Expected Behavior

to be not flaky

e.g.

DataPlaneHttpToHttpIntegrationTests > transfer_WithSourceQueryParams_Success() FAILED
    java.lang.IllegalArgumentException: duplicate key: et
        at java.base/java.util.ImmutableCollections$MapN.<init>(ImmutableCollections.java:830)
        at java.base/java.util.Map.of(Map.java:1327)
        at org.eclipse.dataspaceconnector.dataplane.http.DataPlaneHttpToHttpIntegrationTests.transfer_WithSourceQueryParams_Success(DataPlaneHttpToHttpIntegrationTests.java:179)

Seems to be caused by Faker, as it could gave the same word as key for the map:
https://github.com/eclipse-dataspaceconnector/DataSpaceConnector/blob/82891948f0ebe67de74390ae6a7510aeb6c053da/extensions/data-plane/integration-tests/src/test/java/org/eclipse/dataspaceconnector/dataplane/http/DataPlaneHttpToHttpIntegrationTests.java#L179-L182