fix: Exclude placeholder prop from Modal props

[mdmower-csnw]

Summary

The types generated for Modal props indicate that placeholder is available because @types/react prior to v18.2.43 has placeholder as an attribute in HTMLAttributes. Beginning with @types/react v18.2.43, the placeholder attribute has been removed from HTMLAttributes. As a result, projects that consume this package but are themselves on @types/react v18.2.43 or newer no longer recognize placeholder as an optional property; they see it as stemming from these Modal props rather than JSX.IntrinsicElements['div'], and that it is required, not optional.

Patch Modal to manually omit placeholder from available properties without updating packages, which would require a more significant lift.

Ref: DefinitelyTyped/DefinitelyTyped#67170

How To Test

1. Add react-uswds to a TypeScript project that has a dependency on @types/react v18.2.48.
2. Use the <Modal> component without defining the placeholder attribute.
3. Attempt to build the project -- the TypeScript compiler will report an error that placeholder is required but not defined:

   [tsl] ERROR in /path/sanitized/MyComponent.tsx(95,10) 
      TS2741: Property 'placeholder' is missing in type '{ children: Element[]; ref: RefObject<ModalRef>; "aria-describedby": string; id: string; className: string; }' but required in type 'Pick<ModalProps, "children" | "id" | "onError" | "key" | "aria-label" | "className" | "defaultChecked" | "defaultValue" | "suppressContentEditableWarning" | "suppressHydrationWarning" | ... 249 more ... | "isInitiallyOpen">'.
   

Additional Notes

1. This PR would be obsoleted by feat!: React 18 Upgrade #2714 since that PR also updates @types/react to v18.2.48. That PR requires a major version update though, whereas this fix is safe to apply as a patch update.
2. Modal was verified to be the only component affected by this issue by grepping built lib/components for string "placeholder". The only other component where the placeholder attribute appears explicitly is FileInput and there it is supported (HTMLInputElement instead of HTMLDivElement).

[werdnanoslen]

Hey @mdmower-csnw thanks for this PR! We decided to proceed with #2714 — is there anything in this PR that you'd still like to submit, or should we close this?

[mdmower-csnw]

@werdnanoslen - Thanks, that sounds fine. Feel free to close this.

It's worth keeping this PR in mind if an issue report comes in from a user on v5 or v6 who is not ready to jump to v7. They can either stay on @types/react@18.2.42 or this project could release patch updates to previous major releases (e.g. apply this commit on top of https://github.com/trussworks/react-uswds/tree/5.5.0 and release v5.5.1).

[werdnanoslen]

or this project could release patch updates to previous major releases (e.g. apply this commit on top of https://github.com/trussworks/react-uswds/tree/5.5.0 and release v5.5.1).

Fair point! If anyone requires such a patch—and maybe comments here—we could re-open this PR to apply as you suggested. I'll close for now though.