fix: widget positioning

[BeksOmega]

The basics

• I validated my changes

The details

Resolves

Fixes #7491

Proposed Changes

Reorganizes a bunch of code, and makes it so that fields get onLocationChange call backs.

Reason for Changes

Makes it so that fields can reposition their widgets properly.

Test Coverage

• Tested that RTL input field alignment is off #6976 does not reproduce
• Tested that changing the window size properly repositions the div, re: Soft keyboard issues on Android #6915
• Tested that Modifying the structure of a block does not trigger widgets to be repositioned #7491 does not reproduce
• Tested that we did not get a significant performance drop by dragging spaghetti blocks, and also typing into the spaghetti blocks. We might have gotten a slight performance dip from splitting up the connection update operations so they're not happening contiguously (the engine can't optimize as much). But all of this code is internal so I can circle back once I've had more time to investigate.

old-dragging.txt
new-dragging.txt

Documentation

N/A

Additional Information

Might want to hold until after release?

Deprecations

• TODO

[BeksOmega]

Note to self to ping code.org people about this re: their flyout field if it gets approved. I think they can use this new callback to handle the width of their field less jankily. (Since we call onLocationChange after every render.)