[4.4] Fix Sample data installation, fix finder helper addContentType null value

[Fedik]

Pull Request for Issue # .

Summary of Changes

Helper::addContentType() allows null for mime, however $db->quote() does not.
Same as #43051 but for 4.4

Testing Instructions

Use PHP 8+, set error reaporting to Maximum
On clean installation, try install "Blog Sample Data"

Run following code (example in index.php of the template):

$name = uniqid(); // Imitating a new content type name, can be any string
var_dump(Joomla\Component\Finder\Administrator\Indexer\Helper::addContentType($name));

Actual result BEFORE applying this Pull Request

PHP warning Deprecated: PDO::quote(): Passing null to parameter 1 ($string) of type string is deprecated

Expected result AFTER applying this Pull Request

No warning

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

[toivo]

I have tested this item 🔴 unsuccessfully on 1738f32

Unable to reproduce the error in out-of-the-box Joomla 4.4.4-dev, run in Wampserver 3.3.3 usin PHP 8.2.13 on Windows 11.

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/43052.}

[Fedik]

I have updated test instruction,
old one was more for 5.x.