29577 Refactor computeStyleWithContext + unit tests

[carolinepaulic]

Description

This covers the bulk of https://github.com/allenai/scholar/issues/29577 which is a subtask of the PDF Component Library Loose Ends ticket.

Changes in this PR:

• Style function changes:
  • Moved style computation functions out of the BoundingBox component and into a new styleUtils.ts file
  • Broke computeStyleWithContext up into separate functions for bounding boxes vs page style- computeBoundingBoxStyle and computePageStyle
  • Also split out getPageHeight and getPageWidth functions because getPageWidth is used in other places and I thought getPageHeight should match despite only being used in one place
  • Added a 🛥️ load of unit tests for all of these style functions
• Type changes:
  • Broke Size type up into new Dimensions (height and width) and Origin (left and top) types.
  • Moved Point from scale.ts to types.ts
  • Renamed context variables pageSize/setPageSize to pageDimensions/setPageDimensions to accurately reflect the new type
  • Removed bounding box CSS for min-height that was causing issues with scaling

Reviewer Instructions

Don't be discouraged by how many LOC were changed in this PR! Most of it is variable renaming due to the pageSize > pageDimensions thing and the unit tests added 400+ LOC as well. I tried to split my commits up nicely so you can step through those if that's useful.

Testing Plan

• Manual testing
  • Existing functionality works as expected (zoom, rotate, outline, highlight overlay demo, text highlight demo, scroll to demo)
• Ran all unit tests