Enable _list search resolution securely with Medino

[brendankowitz]

Describe the bug
ListSearchPipeBehavior was not intentionally registered before the Medino migration. Medino assembly scanning can register it automatically, changing behavior as part of PR #5235. When enabled without an authorization behavior running first, _list resolution can short-circuit the normal search handler and bypass search authorization.

PR #5235 should preserve migration parity by suppressing the accidentally scanned ListSearchPipeBehavior. Secure _list enablement should be implemented and reviewed separately rather than expanding the migration PR.

FHIR Version?
Stu3/R4/R5

Data provider?
CosmosDB/SQL Server

To Reproduce
Steps to reproduce the behavior:

1. Register Medino handlers and pipeline behaviors through assembly scanning.
2. Submit a search request using the _list parameter where list resolution returns without invoking the normal search handler.
3. Observe that handler-level search authorization is not reached unless authorization is enforced before list resolution.

Expected behavior
The Medino migration does not activate previously unregistered _list resolution behavior. A focused follow-up change intentionally enables _list resolution only with authorization ordered before it, with security and integration tests covering short-circuit paths.

Actual behavior
Medino scanning can activate ListSearchPipeBehavior unintentionally. Its short-circuit path can return a response before the normal search handler performs authorization.

[evachen96]

#199420