[4.0] Use getIdentity for plugins

[joomdonation]

Pull Request for Issue # .

Summary of Changes

This PR does two things:

• Add $app property to plugins (when it is missing) and use that injected application object to replace Factory::getApplication()
• Use $this->app->getIdentity() to get current user object instead of the deprecated method Factory::getUser();

Testing Instructions

Add it is small changes but target multiple plugins, I prefer to have careful code review here.

[wilsonge]

I excludes system plugins from these changes because I'm unsure if it is safe to use $this->app->getIdentity() method in system plugins yet.

You've included a system plugin :D I'm also unsure though. Action logs (and user plugins) will also be loaded on update - hence why they get the extra warnings in the pre-update checker - so this probably does need a test unless you remove all of those cases

[joomdonation]

You've included a system plugin :D I'm also unsure though

After looking at our Application classes more carefully, I see that the Identity is available very early in application life cycle. It is available in initialise phase, right after Factory::getUser() line is called https://github.com/joomla/joomla-cms/blob/4.0-dev/libraries/src/Application/SiteApplication.php#L621 , long before system plugins are imported and triggered, so it is safe to use $this->app->getIdentity(); to get current logged in user.

With that said, I do the replacement in system plugins, too. Will test with update from Joomla 3.10 to 4.0 to make sure everything is still working OK.

[joomdonation]

So I tested the update from 3.10.0-dev to the package on PR and it is working OK. Tested several features in the CMS like login, logout, action logs, editor-xtds... changes by this PR and it is working OK, too.

[HLeithner]

This pull request has automatically rebased to 4.2-dev.

[laoneo]

Can you fix the conflicts here? Keep in mind that the service provider plugins have the app already injected. Would love to get this merged.

[joomdonation]

There are so many conflicts now, so I'm closing this PR. Will review it at a later time base on latest code from plugins which we are having now.