Fix logic for 'at least one' item

We only show global header/footer if there's at least one item to display.  The header was fine already, but we weren't considering other cases where there were items found in order to decide to display the footer.

So if you had no header visible, but wanted a footer, it wouldn't show up.

Merge pull request #39 from Redth/scrollbarvisibility

Add support for scrollbar visibility

Merge pull request #16 from Redth/scroll-to-item

Fix iOS/MacCat cell tap for selection

Merge pull request #15 from Redth/scroll-to-item

Add ScrollToItem

Merge pull request #14 from Redth/perf-improvements

Perf Improvements & Consistency

Merge pull request #13 from Redth/memory-analyzer-fixes

Memory analyzer fixes

Update deps for net8

Add properties to hide global header/footer

Merge branch 'main' of https://github.com/Redth/Maui.VirtualListView

Merge branch 'main' of https://github.com/Redth/Maui.VirtualListView