fix(labels): format adding new labels in service plan with + modifier

pkg/client/deploy/deploy.go

@@ -332,6 +332,8 @@ func formatLabelsDiff(attribute string, oldLabels, newLabels map[string]string,
 	switch {
 	case isNewService:
 		blockMod = " "
+	case len(oldLabels) == 0:
+		blockMod = tui.Green.Render("+")
 	case len(newLabels) == 0:
 		blockMod = tui.Red.Render("-")
 	}

pkg/client/deploy/deploy_test.go

@@ -205,7 +205,7 @@ func TestServicePlan_Format(t *testing.T) {
 			expected: []string{
 				"~ update service web",
 				"  │   image: nginx:1.25",
-				"  │ ~ labels:",
+				"  │ + labels:",
 				"  │     + a=1",
 				"  │",
 				"  ╰── ~   update container web/0f6df6593e1b on machine-1 (in place)",