Fix Rails login normalized user profile

[jusleg]

Given that session[:userinfo] already maps to raw info, we can no longer show the full user profile by calling session[:userinfo][:extra][:raw_info] as it leads to a NoMethodError. Now, we display the normalized information by using @user directly. This is in line with the changes in the sample repository https://github.com/auth0-samples/auth0-rubyonrails-sample/commit/c0da5862af2e548186ec00771e15e9de1aa75c4a#diff-6c10f94ab4d3763545c6c4868dcbdb21e18335b7dcbd7390bcf5a74c1ce350f7R9

[Widcket]

cc @evansims as you were looking into the Rails QS