Adds ImageMagick.php to blacklist of phpstan

ImageMagick adapter is non default one and can be configured
It is not included in Test Enviroment

Author: krisdante

dev/tests/static/testsuite/Magento/Test/Php/_files/phpstan/blacklist/common.txt

@@ -5,6 +5,7 @@
 # dev/tests/static/framework/bootstrap.php
 lib/internal/Magento/Framework/Interception/Test/Unit/Config/ConfigTest.php
 lib/internal/Magento/Framework/Cache/Backend/Eaccelerator.php
+lib/internal/Magento/Framework/Image/Adapter/ImageMagick.php
 dev/tests/integration/framework/deployTestModules.php
 dev/tests/integration/testsuite/Magento/Framework/Session/ConfigTest.php
 dev/tests/integration/testsuite/Magento/Framework/Session/SessionManagerTest.php