Notidart help me a lot with this problem. With the help of the link I gave, Notidart work on this extension just for testing:
That extension inject a JS file and an Image just for example, and Have Implemented the code that Jai Prakash put on How to add Content Security Policy to Firefox extension and its working well. It injects the file on all sites with a CSP defined.
Thank you very much to both, there is no easy way or documentation for avoid the CSP in Firefox extensions, but this solution works very well.