Add spacing for Floating Panel on Mac Catalyst

[des12437]

The menu items need spacing between the drop down menu label and arrow in the Utility Network Trace example. This issue is only present on Mac Catalyst due to the arrows being left aligned. This may be an issue with the Floating Panel UI layout.

Mac Catlayst:

iPad:

[des12437]

There is also missing spacing for this menu component on Mac Catalyst. The leading and trailing anchors should be aligned with the other UI elements that are centered in the menu.

[dfeinzimer]

@mhdostal I see Popups also uses DisclosureGroups and is seeing tight spacing there as well. Would you like to see that addressed simultaneously?

[mhdostal]

@mhdostal I see Popups also uses DisclosureGroups and is seeing tight spacing there as well. Would you like to see that addressed simultaneously?

Yes, let's make it consistent.