BED-5576: Unset overflow when FixedSizeList has fewer than 2 nodes

[TheNando]

Description

This PR adds a conditional styling override to VirtualizedNodeList. If there are fewer than 2 nodes, overflow will not be applied.

Motivation and Context

This PR addresses: BED-5576

Our VirtualizedNodeList components will display the scrollbar even if single node is rendered. This components uses React Window's FixedSizeList component, which unconditionally applies an 'auto' overflow, causing the scrollbar to always be displayed.

How Has This Been Tested?

Manually tested using demo data set.

Screenshots:

Before (notice DC01.PHANTOM.CORP is slightly cut off at bottom):

After:

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have met the contributing prerequisites
  • Assigned myself to this PR
  • Added the appropriate labels
  • Associated an issue: Issues and Pull Requests README #672
  • Read the Contributing guide: https://github.com/SpecterOps/BloodHound/wiki/Contributing
• I have ensured that related documentation is up-to-date
  • Open API docs
  • Code comments (GoDocs / JSDocs)
• I have followed proper test practices
  • Added/updated tests to cover my changes
  • All new and existing tests passed

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[TheNando]

I have read the CLA Document and I hereby sign the CLA

[elikmiller]

There is a margin being applied by the List component on lines 40-42 - perhaps another solution would be to simply remove that margin?

[elikmiller]

We have implemented a similar virtualized list in our <InfiniteScrollingTable> - this list does not have the top margin. I am not super clear on how these lists are receiving their styles but by removing the top margin from this <VirtualizedNodeList> component we could make the two slightly more uniform.

[elikmiller]

But either solution works so I'll approve your changes and let you decide if you prefer this approach instead!

[TheNando]

I'll dig in a little deeper to compare. Removing the top margin was my first instinct as well. I'll compare the solutions. I know it's tiny issue, but should only take a few mins to compare.

[TheNando]

The margin solution is much cleaner and still has the advantage of applying the fix for all implementations. I think this is probably the better call, though there would still be a potential for a very minor visual regression without checking all places this component is used. But it shouldn't affect functionality and still address this issue.