Non active module dependency throws TypeError in PHP 8+

[Tomasz-Silpion]

Preconditions (*)

1. Any recent version of OpenMage including main branch.
2. Non active module that depends on non existing module.
3. PHP 8.0 or any newer version throwing TypeError for non-array arguments in array_merge().

Steps to reproduce (*)

1. Install recent version of OpenMage
2. In app/etc/modules folder create Vendor_Module.xml with following content:

<?xml version="1.0"?>
<config>
    <modules>
        <Vendor_Module>
            <active>false</active>
            <codePool>local</codePool>
            <depends>
                <Other_Module/>
            </depends>
        </Vendor_Module>
    </modules>
</config>

3. Flush cache if it is enabled.

Expected result (*)

1. No error is thrown, there's no change to the store behavior.
2. Unless module file <active> tag is not set to true Module "Vendor_Module" requires module "Other_Module" exception does not appear.

Actual result (*)

1. Fatal error: Uncaught TypeError: array_merge(): Argument #2 must be of type array, null given in app/code/core/Mage/Core/Model/Config.php:940.