feat: pin api-version to 2026-01-15-preview for Java in CognitiveServices.Management (#42778)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: weidongxu-microsoft

specification/cognitiveservices/CognitiveServices.Management/tspconfig.yaml

@@ -29,6 +29,7 @@ options:
     flavor: azure
     use-object-for-unknown: true
     float32-as-double: false
+    api-version: "2026-01-15-preview"
   "@azure-tools/typespec-ts":
     emitter-output-dir: "{output-dir}/{service-dir}/arm-cognitiveservices"
     flavor: azure