On that engine the plug is at the very bottom of the cylinder if inverted mount. This means any residual fuel will drain to the bottom and into the plug, drowning it. You killed it with the choke, no better way to flood an engine.

Pull the plug out and blow out the residual fuel and goo and dry it off real well, then plug it into the cap and test the ignition by turn on the power and rotating the prop a few times. No need to ground the plug, the cap itself is grounded through the braided sleeve. You should have a nice blue spark.

Reinstall the plug, go fly.

TF