Make IngressInfo.enabled optional (#937)

To provide backward compatibility with already existing Ingresses
---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

Author: biglittlebigben

.changeset/nervous-chicken-sparkle.md

@@ -0,0 +1,5 @@
+---
+"@livekit/protocol": patch
+---
+
+Add "Enabled" flag to ingresses to allow preventing an ingress to become active without deleting it.

infra/link.pb.go

@@ -56,7 +56,7 @@ func ValidateForSerialization(info *livekit.IngressInfo) error {
 		if info.Url == "" {
 			return ErrInvalidIngress("no source URL")
 		}
-		if !info.Enabled {
+		if info.Enabled != nil && !*info.Enabled {
 			return ErrInvalidIngress("disabled non reusable ingress")
 		}
 	}

ingress/validation.go

@@ -143,6 +143,41 @@ func TestValidateEnableTranscoding(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestValidateEnabled(t *testing.T) {
+	info := &livekit.IngressInfo{
+		StreamKey:           "sk",
+		RoomName:            "room_name",
+		ParticipantIdentity: "id",
+	}
+	T := true
+	F := false
+
+	err := Validate(info)
+	require.NoError(t, err)
+
+	info.Enabled = &T
+	err = Validate(info)
+	require.NoError(t, err)
+
+	info.Enabled = &F
+	err = Validate(info)
+	require.NoError(t, err)
+
+	info.InputType = livekit.IngressInput_URL_INPUT
+	info.Url = "url"
+	info.Enabled = nil
+	err = Validate(info)
+	require.NoError(t, err)
+
+	info.Enabled = &T
+	err = Validate(info)
+	require.NoError(t, err)
+
+	info.Enabled = &F
+	err = Validate(info)
+	require.Error(t, err)
+}
+
 func TestValidateVideoOptionsConsistency(t *testing.T) {
 	video := &livekit.IngressVideoOptions{}
 	err := ValidateVideoOptionsConsistency(video)