[XDebug Bridge] Fetch all array keys when inspecting an array - #2409

Motivation for the change, related issues

Fixes two problems:

• Fetches all the array keys when inspecting arrays. property_get XDebug command is paginated and before this PR, we'd only see a subset of all the array keys. With this PR, we see all the keys. This will be a problem on huge arrays so we'll need to bucket keys into group of 1000 in a follow-up PR.
• Supports actually browsing superglobals, e.g. $_SERVER. Before this PR, you'd only see another nested superglobal (see the screenshot below).

As for the latter, I'm not too happy about the solution – we're reaching for the nested XDebug .property.property when it's available. I expect that will lead us astray in some scenarios, e.g. when browsing arrays that have nested arrays. That being said, I couldn't easily break it so let's get it in and continue iterating:

const responseProps =
	response.property?.property ?? response.property;

Testing instructions

Create a file called xdebug.php:

<?php
unset($_SERVER['CLIENT_SECRET'], $_SERVER['CLIENT_ID']);
$test = 42;  // Set a breakpoint on this line

$another = [15, [1,2,3, [4,5,6] ] ];

echo "Output!\n";

function test() {
	echo "Hello Xdebug World!\n";
print_R($_ENV);
print_r($_SERVER);
}

test();

Run nx run php-wasm-cli:dev --xdebug --experimental-devtools xdebug.php before and after this PR. Confirm you see the following results:

Before

After ($_SERVER is still duplicated – let's fix that separately)