feat: use user_info API to check tokens DD-4674

[dmitrytrager]

POST token_info method does not work for checking tokens because it requires access token specific to Account API (our stored tokens are specific to Marketing API). This PR introduces GET user_info method to check token's validity. After this change POST requests support is not needed and can be removed for now.

Examples:

irb(main):001> Panda::Client.new(TiktokProfile.last.token).token_info
(irb):1:in `<main>': Access token is incorrect or has been revoked. (Panda::NotAuthorizedError)

irb(main):002> Panda::Client.new(TiktokProfile.last.token).user_info
=>
#<Panda::UserInfo:0x00000001696ed4e8
 @data={"core_user_id"=>"715585...", "avatar_url"=>"", "display_name"=>"...", "email"=>"a***@revealbot.com", "create_time"=>1666121473}>

TT API: https://business-api.tiktok.com/portal/docs?id=1739665513181185

[AlphaB]

I don't think we need to remove token_info method, it's a public gem after all :) We also might need token_info method in near future