[12.x] Fix remaining PHP 8.5 null index array deprecations

[IonBazan]

Following up #57137 and #57231 - fixing remaining null array index accessors.

Remaining deprecations include:

• PDO::MYSQL_* constants in orchestra/testbench-core - tracked in Fix use of deprecated driver specific PDO constants #57141
• SplObjectStorage::contains() in opis/json-schema - fixing in PHP 8.5 compatibility opis/json-schema#156
• Using null as an array offset is deprecated, use an empty string instead in league/uri - fixed in Fix PHP 8.5 deprecations thephpleague/uri-src#157, unreleased

[shaedrich]

Isn't the problem something else here?

Suggested change

	return is_array($channels[$connection ?? ''] ?? null)
	? $channels[$connection ?? '']
	return (array_key_exists($connection, $channels) && is_array($connectionChannels = $channels[$connection]))
	? $connectionChannels

[IonBazan]

No, we can't pass null to any function that takes array index:

<?php

$arr =[];
var_dump(array_key_exists(null, $arr));

// Deprecated: Using null as the key parameter for array_key_exists() is deprecated, use an empty string instead in /in/KYhLO on line 4
// bool(false)

We'd have to use null-safe operator here too

[shaedrich]

Yeah, that wasn't my point. I added a suggestion for the original code. A suggestion with your changes incorporated would look like this:

Suggested change

	return is_array($channels[$connection ?? ''] ?? null)
	? $channels[$connection ?? '']
	return ($connection !== null && array_key_exists($connection, $channels) && is_array($connectionChannels = $channels[$connection]))
	? $connectionChannels