Remove default props for React 19 compat

[tidychips]

Fixes #709, #763, #774

What did you change (functionally and technically)?
Removes defaultProps for functional components as React 18.3 warns that they're deprecated, and React 19 fully removes support for them.

Checklist (remove this list before you submit the PR)

• Are there tests for the new code? Existing tests cover these changes
• Does the code comply to our code conventions? Yes
• Does the PR resolve the whole issue? Yes

Additional review hints (remove this list before you submit the PR)

• Besides the code review, what should the reviewer test? Regression test previous functionality
• Are there any edge cases? None that I know of
• Do you have any test files or test set-up? No
• Could your changes cause side effects elsewhere in the code base? Yes

[changeset-bot]

🦋 Changeset detected

Latest commit: 517d8e3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
react-mentions	Patch

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Name	Status	Preview	Comments	Updated (UTC)
react-mentions	❌ Failed (Inspect)			May 1, 2025 3:08pm

[hbmartin]

This package looks abandon but I am working to resurrect with a modern rewrite i.e. React 19 and TypeScript 5
https://github.com/hbmartin/react-mentions-ts