Fix deprecated warnings related to using null as an array offset

[B3Hana]

Description (*)

PHP 8.5 deprecated the use of null as an array offset and as a key for the array_key_exists function

Related Pull Requests

• see Prevent PHP 8.5 null-array-offset deprecations in admin options grid renderer #5708

Fixed Issues (if relevant)

• fixes parts of [BUG] PHP 8.5 deprecations are fatal in developer mode (core not clean on 8.5) #5707

Manual testing scenarios (*)

Use the markers below as a guide to replicate the warnings/errors(in dev mode)

• open install setup
• save product without image
• export product
• export customers
• save customer
• save internal product attribute
• open tax rate form

Questions or comments

Mage_Core_Controller_Varien_Action::202 If no action is set, like in install setup
Mage_Catalog_Model_Product_Attribute_Backend_Media::171 If no image was added to the gallery array ('image' => NULL,'small_image' => NULL,'thumbnail' => NULL) while saving
Mage_ImportExport_Model_Export_Entity_Product::529 If a product is not assigned to any category while export
Mage_ImportExport_Model_Export_Entity_Product::666 If a product value is not set for any product while export
Mage_ImportExport_Model_Export_Entity_Customer::405 If a customer value is not set for any customer while saving
Mage_Eav_Model_Config::490 If an internal product attribute is saved (attribute code is disabled)
Mage_Adminhtml_Block_Tax_Rate_Form::146 Varien_Data_Form::125 throws, because no id was set for the tax_rate_title_fieldset

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All automated tests passed successfully (all builds are green, SonarCloud checks are not required to merge)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Hanmac]

@sreichel what would be the best way to fix this check?

It's not possible to have Mage_Adminhtml_Block_Tax_Rate_Title_Fieldset extend from Mage_Core_Block_Abstract because it does extend from Varien_Data_Form_Element_Fieldset

Unless the part is reworked that Mage_Adminhtml_Block_Tax_Rate_Title_Fieldset isn't needed anymore.
Like Mage_Adminhtml_Block_Tax_Rate_Title should implement Varien_Data_Form_Element_Renderer_Interface.