Hey @VladimirSumilin,
I think you’ll find the answer in this earlier post How to query page url value from forge UI KIT - #4 by danielwinterw
There’s further discussion around accessing the URL parameters in the post, How to get the URL of a Forge app in Jira? and an issue was raised to request URL parameters be provided in the context parameters (see FRGE-706 ) which i think would solve your problem - so you might want to add a comment about your use case there to help the team prioritise the issue in the future.
I hope this explains.
Mel