fix: scroll-options fixes and compatibility with custom draggables

[maribethb]

The basics

• I validated my changes

The details

Resolves

Fixes #2354

Proposed Changes

• Converts the plugin to TypeScript because type guards are a good solution to these problems
• Adds type guards for the metrics manager and custom draggables
• Updates the reference to Dragger base class to account for the new location in core
• Adds workspace comments to test page for easier testing
• Adds info to readme about how to use this with other metrics managers and with custom draggables

Reason for Changes

bug bash

no more errors when trying to drag bubbles!

Test Coverage

manual testing

Documentation

updated readme

Additional Information

requesting review from beka to make sure my warning about the custom draggable objects seems legit

also, we had discussed offline if using drag instead of moveDuringDrag would be sufficient, since drag is already present on hte IDraggable interface, and moveDuringDrag is internal. turns out it works fine!

[BeksOmega]

Discussed offline: this needs some early returns so it doesn't throw errors for things that don't have all of the methods it needs. This is because bubbles are draggable and don't have all of the methods it needs :P

Didn't get caught before because this is in JS so we don't get type errors, and I only tested with blocks and workspace comments :/

[maribethb]

Ready for review!