Convert MiradorShareDialog and MiradorShareEmbed to function compontents

[lutzhelm]

No description provided.

[lutzhelm]

This is weird. npm actually chooses 19.1.0 for both react-dom and react, but in the v4.0.0-alpha.16 Mirador ES build, there is a very strange hardcoded version check in line 25240:

      if (a !== "19.0.0")
        throw Error(
          `Incompatible React versions: The "react" and "react-dom" packages must have the exact same version. Instead got:
  - react:      ` + (a + `
  - react-dom:  19.0.0
Learn more: https://react.dev/warnings/version-mismatch`)
        );

[marlo-longley]

Confirming that this error is happening on the current main branch of the share plugin, not just this PR branch. Looking at it now...