feat(chat-e2e): changed nested entities creation logic

Description:

changed nested entities creation logic

Checklist:

[x] the pull request name complies with Conventional Commits
[x] the pull request name starts with fix(<scope>):, feat(<scope>):, feature(<scope>):, chore(<scope>):, hotfix(<scope>): or e2e(<scope>):. If contains breaking changes then the pull request name must start with fix(<scope>)!:, feat(<scope>)!:, feature(<scope>)!:, chore(<scope>)!:, hotfix(<scope>)!: or e2e(<scope>)!: where <scope> is name of affected project: chat, chat-e2e, overlay, shared, sandbox-overlay, etc.
[ ] the pull request name ends with (Issue #<TICKET_ID>) (comma-separated list of issues)
[x] I confirm that do not share any confidential information like API keys or any other secrets and private URLs

epam / ai-dial-chat