Removed client-side username checks (#3444)

[joechrisellis]

Fairly simple fix I think, just removing the client side tests when authenticating with the server. An error will still be raised iff the server determines the username to be invalid, but client side checks are no longer in place. This means that it's completely at the discretion of the server to decide whether or not a username is valid or invalid.

As I mentioned in #3444, the client side checks made it impossible to authenticate with an Artifactory instance using SAML SSO using the prompts in conan upload. The removal of these checks should fix this. I haven't yet been able to test whether or not Artifactory will deem email addresses to be OK -- I can check this Wednesday. But I think now the onus is on Artifactory to exhibit the correct behaviour rather than any bug in conan.

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Changelog: Fix: Removed login username syntax checks that were no longer necessary.

[memsharded]

I am not sure about this. The implementation is:

class Username(str):

    def __new__(cls, name):
        """Simple name creation.

        @param name:        string containing the desired name
        """
        ConanName.validate_user(name)
        return str.__new__(cls, name)

So it will still raise if validate_user() pattern is not fullfilled. Sounds a test would help to make sure it is working as expected.

[joechrisellis]

You're right -- I got a different err msg after this change and assumed it was sent over from the server. On further inspection it's just displaying the exception message from models/ref.py.

[memsharded]

The implementation now seems correct. However, to make it a complete change, it would be necessary:

• To remove the Username class from the code. It is not used anywhere else, it is dead code now
• To remove the username_test, that is testing such unused class.
• A new test that proves that characters not valid in the name field of a conan_ref, like @ are indeed allowed now.

The first two are easy, just remove them. The last one might be a bit more complicated, but the TestClient allows in the constructor the user field which accepts user-password to be used in auth, that would be enough to test it. Ask for help if needed, thanks :)

[joechrisellis]

Added tests and rm the dead code, let me know if this is ok :)

[memsharded]

Excellent, thank you!