Update FormTypeCsrfExtension.php

There is no need to store the FormFactory in an Attribute.
The FormFactory can be retrieved directly.
minor#9120 Update FormTypeCsrfExtension.php (tweini)

This PR was merged into the master branch.

Discussion
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Update FormTypeCsrfExtension.php

There is no need to store the FormFactory in an Attribute.
The FormFactory can be retrieved directly.

Commits
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90d59ea Update FormTypeCsrfExtension.php