DialogPrimitiveBody - revert change to tabindex (HDS-5585) (#3350)

Author: KristinLBradley

.changeset/heavy-impalas-call.md

@@ -2,6 +2,6 @@
   Copyright (c) HashiCorp, Inc.
   SPDX-License-Identifier: MPL-2.0
 }}
-<div class="hds-dialog-primitive__body {{@contextualClass}}" tabindex="-1" ...attributes>
+<div class="hds-dialog-primitive__body {{@contextualClass}}" tabindex="0" ...attributes>
   {{yield}}
 </div>