[doc] Update xDS features doc with latest for Node as of 1.12.0 (#38266)

The only change relative to the previous update is the addition of dualstack backend support in 1.12.0. I also added server support without the security changes in 1.11.0, but there isn't a separate table entry for that.

Closes #38266

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/38266 from murgatroid99:xds_features_node_update_1.12.0 655876daf8
PiperOrigin-RevId: 723552436

doc/grpc_xds_features.md

@@ -82,4 +82,4 @@ mTLS Credentials in xDS Bootstrap File | [A65](https://github.com/grpc/proposal/
 Stateful Session Affinity | [A55](https://github.com/grpc/proposal/blob/master/A55-xds-stateful-session-affinity.md), [A60](https://github.com/grpc/proposal/blob/master/A60-xds-stateful-session-affinity-weighted-clusters.md), [A75](https://github.com/grpc/proposal/blob/master/A75-xds-aggregate-cluster-behavior-fixes.md) | v1.61.0 | | | |
 xDS Locality label for OpenTelemetry metrics | [A78](https://github.com/grpc/proposal/blob/master/A78-grpc-metrics-wrr-pf-xds.md) | v1.63.0 (C++) | v1.64.0 | | |
 xDS Fallback | [A71](https://github.com/grpc/proposal/blob/master/A71-xds-fallback.md) | v1.67.0 | | | |
-Dualstack Backend Support | [A61](https://github.com/grpc/proposal/blob/master/A61-IPv4-IPv6-dualstack-backends.md) | v1.66.1 | | | |
+Dualstack Backend Support | [A61](https://github.com/grpc/proposal/blob/master/A61-IPv4-IPv6-dualstack-backends.md) | v1.66.1 | | | v1.12.0 |