Bump api-version to 2026-04-01 (#43844)

Author: audunn

specification/netapp/resource-manager/Microsoft.NetApp/NetApp/tspconfig.yaml

@@ -28,7 +28,7 @@ options:
     float32-as-double: false
     client-side-validations: true
     uuid-as-string: false
-    api-version: "2026-01-01"
+    api-version: "2026-04-01"
   "@azure-tools/typespec-ts":
     emitter-output-dir: "{output-dir}/{service-dir}/arm-netapp"
     flavor: azure
@@ -49,6 +49,7 @@ options:
     generate-fakes: true
     head-as-boolean: true
     inject-spans: true
+    api-version: "2026-04-01"
 
 linter:
   extends: