[6.0] Prevent error when cache of language file broken

[joomdonation]

Pull Request for Issue #46499.

Summary of Changes

PR #45289 introduced language caching to improve performance. However, it might causes error as described in the plugin #46499 if the cache file is corrupted for some reasons. This PR adds some code to prevent that. In case the included cache file does not return array, the cache file will be deleted so that it will be re-generated.

Testing Instructions

• Uses Joomla 6
• Look at administrator\cache\language folder, find the file administrator-language-en-GB-plg_system_guidedtours.ini.XYX.php, edit it, change the content to just the code below to make it broken:

<?php
defined('_JEXEC') or die;

• Access to administrator area of your site. You should see fatal error

Actual result BEFORE applying this Pull Request

You get fatal error

Expected result AFTER applying this Pull Request

No error, even if cacch language file is broken

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[exlemor]

I have tested this item ✅ successfully on cada051

I have tested this successfully, Thank you @joomdonation!

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[alikon]

I have tested this item ✅ successfully on cada051

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/46541.}

[alikon]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/46541.}

[Lacis]

Remove admin/cache, language fold+ autoload_psr4.php, copied J601 admin/language and language folder.

[joomdonation]

@Lacis Your last comment is not very clear. Could you please explain more details about it?