Bug on initiatives due to description length

Trying to promote an Initiative, on Start step, if description text is too long, the system returns an error message: "There was a problem with our server. Please try again later.", and there's no indicator/counter of how many characters are allowed and how many are left while writing.

We should add a counter of character to description field, as the one you find on Title field, and it should show you if there's a problem on that before you press Continue botton and after you click on it, instead of the server error message that appears now.

- Device OS: Ubuntu 22.04
- Browser: Brave
- Decidim Version: v.0.26.2 & 0.27.0.rc2
- Decidim installation: decidim.barcelona & meta.decidim.org