* [OPIK-996] user comments for traces/spans

* [OPIK-996] fix max length for user form

* [OPIK-996] UI improvements

* [OPIK-996] hide username and avatar for local env

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Co-authored-by: Yaroslav Boiko <yaroslavboiko@ip-192-168-1-15.ec2.internal>
Co-authored-by: Yaroslav Boiko <yaroslavboiko@ip-192-168-1-19.ec2.internal>