Display update information of individual components only if we are not running in a Docker container

[yubiuser]

What does this PR aim to accomplish?:

Ports some v5 logic to v6.

web/scripts/pi-hole/php/update_checker.php

Lines 82 to 100 in 5c8945c

	// Version comparison
	if ($docker_current) {
	// It's a container: do not check for individual component updates
	if ($docker_current == 'nightly' || $docker_current == 'dev') {
	// Special container - no update messages
	$docker_update = false;
	} else {
	$docker_update = checkUpdate($docker_current, $docker_latest);
	}
	} else {
	// Components comparison
	$core_update = checkUpdate($core_current, $core_latest);
	$web_update = checkUpdate($web_current, $web_latest);
	$FTL_update = checkUpdate($FTL_current, $FTL_latest);
	// Not a docker container
	$docker_update = false;
	}
	}

Mitigates https://discourse.pi-hole.net/t/v6-docker-not-updating/73670

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