Ability to suppress embeds

[heimskr]

This change adds the ability to suppress embeds in a message from another user through a combination of dpp::message::suppress_embeds(bool) and dpp::cluster::message_edit_flags.

Code change checklist

• [x] I have ensured that all methods and functions are fully documented using doxygen style comments.
• [x] My code follows the coding style guide.
• [x] I tested that my change works before raising the PR.
• [x] I have ensured that I did not break any existing API calls.
• [x] I have not built my pull request using AI, a static analysis tool or similar without any human oversight.

[netlify[bot]]

✅ Deploy Preview for dpp-dev ready!

Name	Link
🔨 Latest commit	3c3ab1607de3c964f68b693dfd7cdfb3b81e45f9
🔍 Latest deploy log	https://app.netlify.com/sites/dpp-dev/deploys/65f37ec6e70bd00008181a71
😎 Deploy Preview	https://deploy-preview-1107--dpp-dev.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.