Revert "nixos/home-assistant: do not set server_host by default"

This reverts commit 62ac81aaf9.

The server_host deprecation has been reverted, so we're going back to
defaulting it to dualstack wildcard.

nixos/modules/services/home-automation/home-assistant.nix

@@ -406,15 +406,14 @@ in
             http = {
               # https://www.home-assistant.io/integrations/http/
               server_host = mkOption {
-                type = types.nullOr (types.either types.str (types.listOf types.str));
-                default = null;
-                example = [
-                  "::1"
-                  "127.0.0.1"
+                type = types.either types.str (types.listOf types.str);
+                default = [
+                  "0.0.0.0"
+                  "::"
                 ];
+                example = "::1";
                 description = ''
-                  Only listen to incoming requests on specific IP/host.
-                  The option is unset by default, meaning that Home Assistant listens on all available addresses.
+                  Only listen to incoming requests on specific IP/host. The default listed assumes support for IPv4 and IPv6.
                 '';
               };