Deprecate HdsModal and HdsFlyout yielded subcomponents (#3222)

Author: zamoore

.changeset/bitter-baboons-tease.md

@@ -0,0 +1,11 @@
+---
+"@hashicorp/design-system-components": major
+---
+
+<!-- START components/flyout -->
+`Flyout` - Removed deprecated `HdsFlyoutHeader`, `HdsFlyoutBody`, `HdsFlyoutDescription`, and `HdsFlyoutFooter` subcomponents.
+<!-- END -->
+
+<!-- START components/modal -->
+`Modal` - Removed deprecated `HdsModalHeader`, `HdsModalBody`, and `HdsModalFooter` subcomponents.
+<!-- END -->