[BUGFIX] Access class property closure correctly

[eliashaeussler]

Accessing the property closure directly throws an exception:

> typo3cms install:generatepackagestates
                                                                               
  [ Error ]                                                                    
  Call to undefined method Helhum\Typo3Console\CompatibilityClassLoader::includeFile()                                                                    
                                                                               
Exception trace:
#0 ()
   app/vendor/helhum/typo3-console/Classes/Compatibility/CompatibilityClassLoader.php:66
#1 Helhum\Typo3Console\CompatibilityClassLoader->loadClass()
#2 spl_autoload_call()
   app/vendor/helhum/typo3-console/Classes/Console/Core/Kernel.php:94
#3 Helhum\Typo3Console\Core\Kernel->handle()
   app/vendor/helhum/typo3-console/Scripts/typo3-console.php:31
#4 {closure}()
   app/vendor/helhum/typo3-console/Scripts/typo3-console.php:33
#5 require()
   app/vendor/helhum/typo3-console/typo3cms:2
#6 include()
   app/vendor/bin/typo3cms:115

Related: #1082
Resolves: #1081

[helhum]

Uhm yes, sorry. I should have fixed the CI for 6.x branch...