feat(app-panel): improve parameter UI

[phoman14]

Changes

Updates the Code Ocean app panel parameter UI for the plot pca 2D capsule.

• update count_type to list with raw, clean, filt, norm options (default: filt).
• move count_type to first position in Basic category.
• update legend_position parameter(s) to list with top, bottom, left, right options.
• convert PCA booleans to lists.
• reorganize PCA panel categories.
• adjust PCA panel parameter order.

Issues

No linked issue.

PR Checklist

(Strikethrough any points that are not applicable.)

• This comment contains a description of changes with justifications, with any relevant issues linked.
• Run the capsule in Code Ocean and ensure it completes successfully with no errors.
• Update CHANGELOG.md with a short description of any user-facing changes and reference the PR number. Follow the style described in https://style.tidyverse.org/news.html
• The tests workflow succeeds on the latest commit.

[kelly-sovacool]

looks good, just a minor change for the changelog

[kelly-sovacool]

Suggested change

- Added tests for the plot pca 2D capsule Code Ocean panel and CLI contract (#1, @phoman14).

not a user-facing change