[5.3] onContentPrepareForm should return void instead of boolean

[joomdonation]

Pull Request for Issue # .

Summary of Changes

While review code of the already merged PR #43426, I found a small issue with the code. The onContentPrepareForm method of ConfirmConsent class should not return boolean value, it should return void instead, like in the System - Fields plugin code https://github.com/joomla/joomla-cms/blob/5.3-dev/plugins/system/fields/src/Extension/Fields.php#L247

In general, when converting our plugins to use SubscriberInterface, the event listeners should always return void. If we need to pass result back, use $event->addResult method instead of return command

Testing Instructions

Code review should be enough

Actual result BEFORE applying this Pull Request

Works

Expected result AFTER applying this Pull Request

Works

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

[laoneo]

Thank you!

[joomdonation]

Thanks @laoneo for the quick merge !