fix: chatbot iframe post message origin

[RonenMars]

Description

Fixed chatbot iframe postMessage origin handling by centralizing target origin logic, simplifying validation, and improving code quality with reduced error noise.

What type of PR is this? (check all applicable)

• 💡 (feat) - A new feature (non-breaking change which adds functionality)
• 🔄 (refactor) - Code Refactoring - A code change that neither fixes a bug nor adds a feature
• 🐞 (fix) - Bug Fix (non-breaking change which fixes an issue)
• 🏎 (perf) - Optimization
• 📄 (docs) - Documentation - Documentation only changes
• 📄 (test) - Tests - Adding missing tests or correcting existing tests
• ⚙️ (ci) - Continuous Integrations - Changes to our CI configuration files and scripts (example scopes: Travis, Circle, BrowserStack, SauceLabs)
• ☑️ (chore) - Chores - Other changes that don't modify src or test files
• ↩️ (revert) - Reverts - Reverts a previous commit(s).