LDEV-1978: Check for Lesson's allowed users rather than ToolSession's ones, because an unathorised access to some Tool's Learner creates a separate ToolSession for that singe user (so he is an allowed person).
LDEV-1616: Add hidden fields so first and last name are submitted even if they are disabled by Partial Profile Editing. Fix validation error messages overwriting.
LDEV-2744: Major clean up and optimisation performed. The servlet uses LAMS logging mechanism. Return messages are sent by the servlet because they are not generated on new CKEditor side.