key_exists() is not treated as an alias of array_key_exists()

[lens0021]

https://psalm.dev/r/6cf8c987e4

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/6cf8c987e4

<?php

/**
 * @return array{
 * 	foo?: string,
 * }
 */
function foo() {
    return array_filter([
        'foo' => rand(0,1) === 1 ? 'foo' : null,
    ]);
}

$foo = foo();
if (array_key_exists('foo', $foo)) {
    echo $foo['foo'];
}

if (key_exists('foo', $foo)) {
    echo $foo['foo'];
}

Psalm output (using commit 7233f38):

ERROR: PossiblyUndefinedArrayOffset - 20:10 - Possibly undefined array key $foo['foo'] on array{foo?: string}