Azure Service Bus session handling: 2 of 6 end_to_end tests fail deterministically (class excluded from CI as [Flaky])

[jeremydmiller]

Split out of #3786 as that issue's in-file note explicitly instructs ("Needs its own issue; do not fold it back into GH-3786"). Filing it because that TODO was never actioned: the class is excluded from CI and nothing tracks the defect.

Wolverine.AzureServiceBus.Tests.end_to_end is tagged [Trait("Category", "Flaky")], which removes 6 tests from CI. It is not flaky. Re-measured 2026-08-02 after the entity-name sanitizing fix, on a freshly recreated emulator (2.0.1):

• 2 of 6 fail, deterministically. The other 4 pass.
• 2.1m for the class, with no broker-initialization timeout anywhere in it — so this is not the provisioning failure Conventional routing on Azure Service Bus fails broker initialization (hidden behind [Flaky] since March) #3786 fixed.

The two failures are both session handling, which conventional routing never touched:

• send_and_receive_multiple_messages_to_queue_with_session_identifier
• split_messages_with_different_sessionids_into_separate_batches

Possibly related to the session-listener work described in #3494.

Fixing this should let the Flaky tag come off the class and return all 6 tests to CIAzureServiceBus.