fix(mgt-react): migrates to modern React rendering

[tobi1220]

Closes #3412

PR Type

Bugfix

Description of the changes

The package mgt-react doesn't work under React 19 because it uses React's deprecated render() (docs) function to render its components. From React 18 and onward , the function createRoot() (docs) should be used. This PR applies the simple changes demonstrated in React's official migration guide. Thus, this will drop support for the deprecated React 17.

PR checklist

• Project builds (yarn build) and changes have been tested in at least two supported browsers (Edge + non-Chromium based browser)
• All public APIs (classes, methods, etc) have been documented following the jsdoc syntax
• Stories have been added and existing stories have been tested
• Added appropriate documentation. Docs PR:

• License header has been added to all new source files (yarn setLicense)
• Contains NO breaking changes

Other information

[microsoft-github-policy-service]

Thank you for creating a Pull Request @@tobi1220.

This is a checklist for the PR reviewer(s) to complete before approving and merging this PR:

• I have verified a documentation PR has been linked and is approved (or not applicable)
• I have ran this PR locally and have tested the fix/feature
• I have verified that stories have been added to storybook (or not applicable)
• I have tested existing stories in storybook to verify no regression has occured
• I have tested the solution in at least two browsers (Edge + 1 non-Chromium based browser)

[tobi1220]

@microsoft-github-policy-service agree

[tobi1220]

@Mnickii Did you by any chance happen to take a loot at this already?

[gavinbarron]

@tobi1220 thanks for this proposal.
IMO this is a breaking change as it will break the library for any folks still using React 17, so I'm going to hold off merging this until I've had a chance to chat with the team and see if there are another items that we'd want to address which would be breaking changes to bundle them into a single major version bump.

[gavinbarron]

@tobi1220

We can't take this change as it would break MGT functionality inside of SharePoint Framework solutions at present. Given that is our most common use case based on metrics we cannot have that level of impact at present.