chore: Refactor & Improve Livechat Widget API (#30924)

.changeset/orange-dragons-fly.md

packages/livechat/.storybook/helpers.tsx

packages/livechat/src/components/App/App.tsx

packages/livechat/src/components/Screen/ScreenProvider.tsx

packages/livechat/src/components/Screen/index.js

packages/livechat/src/definitions/agents.d.ts

packages/livechat/src/definitions/global.d.ts

packages/livechat/src/definitions/guest.d.ts

packages/livechat/src/helpers/canRenderMessage.ts

packages/livechat/src/helpers/formatAgent.ts

packages/livechat/src/helpers/isDefined.ts

packages/livechat/src/lib/hooks.ts

packages/livechat/src/lib/parentCall.ts

packages/livechat/src/lib/room.js

packages/livechat/src/lib/triggers.js

packages/livechat/src/routes/Chat/connector.tsx

packages/livechat/src/routes/Chat/container.js

packages/livechat/src/routes/Chat/stories.tsx

packages/livechat/src/routes/ChatFinished/component.js

packages/livechat/src/routes/ChatFinished/component.tsx