ipn/ipnlocal,tailcfg: communicate to control whether funnel is enabled (#14688)

Adds a new Hostinfo.IngressEnabled bool field that holds whether
funnel is currently enabled for the node. Triggers control update
when this value changes.
Bumps capver so that control can distinguish the new field being false
vs non-existant in previous clients.

This is part of a fix for an issue where nodes with any AllowFunnel
block set in their serve config are being displayed as if actively
routing funnel traffic in the admin panel.

Updates tailscale/tailscale#11572
Updates tailscale/corp#25931

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

tailcfg/tailcfg_test.go

@@ -51,6 +51,7 @@ func TestHostinfoEqual(t *testing.T) {
 		"ShareeNode",
 		"NoLogsNoSupport",
 		"WireIngress",
+		"IngressEnabled",
 		"AllowsUpdate",
 		"Machine",
 		"GoArch",
@@ -251,6 +252,26 @@ func TestHostinfoEqual(t *testing.T) {
 			&Hostinfo{},
 			false,
 		},
+		{
+			&Hostinfo{IngressEnabled: true},
+			&Hostinfo{},
+			false,
+		},
+		{
+			&Hostinfo{IngressEnabled: true},
+			&Hostinfo{IngressEnabled: true},
+			true,
+		},
+		{
+			&Hostinfo{IngressEnabled: false},
+			&Hostinfo{},
+			true,
+		},
+		{
+			&Hostinfo{IngressEnabled: false},
+			&Hostinfo{IngressEnabled: true},
+			false,
+		},
 	}
 	for i, tt := range tests {
 		got := tt.a.Equal(tt.b)