add property hideChildren to GroupsDiagram and GroupsExplorerContent

[benjidotsh]

trafficstars

Hey, I just made a Pull Request!

I've added a property hideChildren to the GroupsDiagram and GroupsExplorerContent components. If you have a lot of groups with a lot of children and you only care about the parent groups, this can greatly improve visibility.

An example of what a GroupsDiagram looks like with hideChildren set to true:

:heavy_check_mark: Checklist

• [x] A changeset describing the change and affected packages. (more info)
• [x] Screenshots attached (for UI changes)
• [x] All your commits have a Signed-off-by line in the message. (more info)

[benjidotsh]

I don't think the pipeline failing is related to my changes, but feel free to let me know if I need to change anything.

[backstage-goalie[bot]]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@backstage-community/plugin-explore	workspaces/explore/plugins/explore	patch	v0.4.21

[benjdlambert]

This looks good, is there a possibility we could add some tests here too? :pray:

[benjidotsh]

@benjdlambert I'll see what I can do - I don't have much experience with writing Backstage tests, but I'll look into it :)

[benjidotsh]

@benjdlambert done!

Please let me know if something is still missing.