feat(overlay): improve ready to interact event and add conversation loaded event (Issue #1578)

Description:

Previously ready to interact called right after models loaded and overlay settings set, but we should also wait for conversation loaded, because we cannot get all needed info from it (like messages and their state) Currently ready to interact event sent once after conversation loaded and if it's not sent before Also added conversation loaded event for cases when we are switching conversation and need to tell about this to host

Issues:

Issue #1578

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.
[x] the pull request name ends with (Issue #<TICKET_ID>) (comma-separated list of issues)
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epam / ai-dial-chat

feat(overlay): improve ready to interact event and add conversation loaded event (Issue #1578) #1649