Avoid possible error when reading groups in debug mode

[westonruter]

This addresses a support forum topic:

Cannot read properties of undefined (reading ‘groups’)

detect.min.js?ver=1.0.0-beta3:1 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading ‘groups’)
at detect (detect.min.js?ver=1.0.0-beta3:1:3066)
at :2:127

The location where this error is occurring:

performance/plugins/optimization-detective/detect.js

Lines 558 to 560 in 85001b9

	if ( isDebug ) {
	const allUrlMetrics = /** @type Array<UrlMetricDebugData> */ [];
	for ( const group of urlMetricGroupCollection.groups ) {

Normally the urlMetricGroupCollection is always populated when WP_DEBUG is true:

performance/plugins/optimization-detective/detection.php

Lines 148 to 150 in 85001b9

	if ( WP_DEBUG ) {
	$detect_args['urlMetricGroupCollection'] = $group_collection;
	}

However, it seems at least in this case here, the HTML had been mutated to remove that object being passed to detect(). So this PR hardens the logic to prevent an error from happening.

Additionally, there is another benefit. Often when debugging Optimization Detective for sites in the wild, I'll use local overrides in Chrome to modify the HTML as follows:

1. Set isDebug to true
2. Replace detect.min.js with detect.js

However, when I do this, I then also need to open up detect.js and add another override to comment out this same line that tries to read from the group. By checking first to make sure that the property exists and is an array, then this will no longer be necessary when debugging sites in the field.

[github-actions]

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Co-authored-by: westonruter <westonruter@git.wordpress.org>
Co-authored-by: ShyamGadde <shyamgadde@git.wordpress.org>

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[ShyamGadde]

LGTM 🚀