fix: Publish WidgetPanelProps

[mofojed]

• Wasn't being published, needed for the DHE refactoring of core plugins
  • Specifically: https://github.com/deephaven-ent/iris/pull/2114/files#diff-536d6ac232028a4ebbafc5ca79bb1a22844488a4b628196e43056379f9326a90R17

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 46.75%. Comparing base (0994c52) to head (1a6e830). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2210 +/- ## ======================================= Coverage 46.75% 46.75% ======================================= Files 694 694 Lines 38637 38637 Branches 9783 9783 ======================================= Hits 18063 18063 Misses 20521 20521 Partials 53 53 ``` | [Flag](https://app.codecov.io/gh/deephaven/web-client-ui/pull/2210/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deephaven) | Coverage Δ | | |---|---|---| | [unit](https://app.codecov.io/gh/deephaven/web-client-ui/pull/2210/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deephaven) | `46.75% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deephaven#carryforward-flags-in-the-pull-request-comment) to find out more.

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