[ISSUE-922] - un-restrict user attribute type definition, add tests...

[victor-optimizely]

Summary

• Reverts functionality for the type definition on user attributes (allow any type)
• adds some tests

Test plan

See [#922]

Issues

• Fixes [OptimizelyProvider UserAttributes Type Definition mismatch] The type definition for the user attributes does not match the documentation and is limiting types allowed #922

[coveralls]

coverage: 90.327% (+0.01%) from 90.313%
when pulling 5d9b52d on victor-optimizely:issues/922
into 75418da on optimizely:master.

[mikechu-optimizely]

Thanks for the collab. Can I ask your use-case where the specific types are causing problems?

[victor-optimizely]

Our team deals with the admin center. We were setting the user's current instance object as a value here. After further investigation we are no longer using any of the fields in the object and moving forward we can just set the specific field we'll use. Since we're updating from 2.X -> 3.X a breaking change is expected I will close this in favor of the documentation being updated. Thanks for looking into it.