Workflow node connector improvements

[ElectronicBlueberry]

closes #17195

Makes several quality of life changes to the input connectors on workflow nodes.

• Node drop area is now larger, expanding beyond the input connector point on every direction
• Node drop area is now square, allowing for additional leeway when attaching connections
• The entire node input can now be used to attach a node to
• When a connection will be made on drop, the input is highlighted

(the cursor is a dragging hand, but my screenshot software can unfortunately not capture it in that state)

Additionally fixes two minor bugs

• Node connector no longer snaps when snapping is active
• Tooltip no longer appears on input nodes when empty

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[bgruening]

Thanks @ElectronicBlueberry