Connection: fix a fatal triggered by disconnecting too early (#44435)

Fix a fatal triggered by trying to disconnect Jetpack too early.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/16574576818

Upstream-Ref: Automattic/jetpack@59c3688

Author: sergeymitr

composer.json

@@ -6,7 +6,7 @@
 	"require": {
 		"php": ">=7.2",
 		"automattic/jetpack-assets": "^4.3.0",
-		"automattic/jetpack-connection": "^6.16.0",
+		"automattic/jetpack-connection": "^6.16.1-alpha",
 		"automattic/jetpack-constants": "^3.0.8",
 		"automattic/jetpack-status": "^6.1.0-alpha"
 	},