Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: resolves #24139

With the Custom Elements build, we now need to call initialize(): https://github.com/ionic-team/ionic-framework/blob/next/packages/react/src/components/index.ts#L202. The problem is that this call also sets up the Ionic config. Given that Ionic config is not designed to be reactive, subsequent calls to setupConfig had no effect.

What is the new behavior?

• After discussing with the team, we feel the best path forward is a (small) breaking change. Developers will be required to add setupIonicReact to their App.tsx/App.jsx file. This function will call initialize and allow developers to pass in a config, so it can be used instead of setupConfig.
• We explored non-breaking change options, but we think this change is the best option long term.
• I also noticed that setupConfig was being exported from Angular/React/Vue packages when it should not be. Developers should be going through the main entry points and not calling setupConfig on their own. If they need to eject from the normal process, they should call initialize instead.

Does this introduce a breaking change?

• Yes
• No

Other information

Migration:

1. Import setupIonicReact from '@ionic/react';
2. In App.tsx, call setupIonicReact();. Config should be passed here instead of setupConfig.
3. Remove any calls to setupConfig.