fixup! diagnostics_channel: replace using with try-finally

Signed-off-by: Ayush Chaudhary <ayush23chaudhary@gmail.com>

Author: ayush23chaudhary

lib/diagnostics_channel.js

@@ -689,4 +689,4 @@ module.exports = {
   boundedChannel,
   Channel,
   BoundedChannel,
-};
+};