Improve the InstallException message

Problem/Motivation

I ran into an InstallException ( 🐛 InstallException when trying to install Pathauto via the ProjectBrowser UI Postponed: needs info ) when trying to install Pathauto via the Project Browser UI.

the current error message recommends that the page is restored from a code base backup. me as a user wasn't aware that there is the possibility that an installation could get corrupted requiring/recommending a restore from backup. for automatic updates there is the recommendation reminding the user to back up their data- and codebase before starting an update #3239759: Remind users to back up their database before starting an update → , for project browser there isn't any. but in this case without a backup at hand, from a users perspective i would feel helpless based on that type of error and given recommendation.

Steps to reproduce

Proposed resolution

• it might be an idea to add a word of warning on /admin/config/development/project_browser in addition to the experimental label for the allow installing via the UI maybe or instead add a reminder on /admin/modules/browse in case the install via the UI option is active.
• the error message shown in the screenshot might be improved as well as @timplunkett suggested in a thread on slack

Remaining tasks

• ✅ File an issue about this project
• ☐ Manual Testing
• ☐ Code Review
• ☐ Accessibility Review
• ☐ Automated tests needed/written?