DRIVERS-3106 note cryptSharedLibPath may be set by test runner (#1817)

Intended to avoid errors loading `crypt_shared` from two different paths. Other tests may already pass an explicit `cryptSharedLibPath`.

Author: kevinAlbs

source/unified-test-format/unified-test-format.md

@@ -530,6 +530,9 @@ The structure of this object is as follows:
         - `schemaMap`: Optional object. Maps namespaces to CSFLE schemas.
         - `encryptedFieldsMap`: Optional object. Maps namespaces to QE schemas.
         - `extraOptions`: Optional object. Configuration options for the encryption library.
+            - If `extraOptions` is not present or omits `cryptSharedLibPath`, test runners MAY set `cryptSharedLibPath` to the
+                path of [crypt_shared](../client-side-encryption/client-side-encryption.md#crypt_shared) being tested. This
+                can avoid test errors loading crypt_shared from different paths.
         - `bypassQueryAnalysis`: Optional. Disables analysis of outgoing commands. Defaults to `false`.
         - `keyExpirationMS`: The same as in [`clientEncryption`](#entity_clientEncryption).
 
@@ -3413,6 +3416,8 @@ other specs *and* collating spec changes developed in parallel or during the sam
 
 ## Changelog
 
+- 2025-07-15: Clarify test runner may apply a default `cryptSharedLibPath`.
+
 - 2025-06-10: **Schema version 1.24.**
 
     Deprecate `storeEventsAsEntities` option for client entities and `loop` operation in the schema and remove them from