User agent still set to experimental

[qstokkink]

This is leftover from the experimental branch:

tribler/src/tribler/core/libtorrent/download_manager/download_manager.py

Lines 302 to 308 in 26db291

	settings["user_agent"] = "Tribler/Experimental"
	enable_utp = self.config.get("libtorrent/utp")
	settings["enable_outgoing_utp"] = enable_utp
	settings["enable_incoming_utp"] = enable_utp
	settings["prefer_rc4"] = True
	settings["listen_interfaces"] = f"0.0.0.0:{libtorrent_port or 6881}"
	settings["handshake_client_version"] = "Tribler/Experimental"

[qstokkink]

Setting settings['user_agent'] = 'Tribler/' + version_id and omitting handshake_client_version seems like a good resolution.