This was the only thing blocking me from signing off on #9224 in 1.7.
! CHANGE WARNING !
If we bind to `T.S.M.Command`s in XAML, then the compiler gets _very
angry_ at us. It generates two different versions of
`GetReferenceTypeMember_Icon` in `XamlTypeInfo.g.cpp`. Presumably
because there's an Icon on a NavViewItem and an Icon on a Command. We
don't really know why. Fortunately, the fix is "rename Command::Icon" to
"Command::IconPath". It's dumb, but it works. Thanks for the help with
that one Carlos ☺️
Unblocks #9224
First step towards #8415:
* Introduce `PaletteItem` and derive from it to provide native support
for tabs and command lines (`ActionPaletteItem` / `TabPaletteItem`,
`CommandLinePaltteItem`)
* Remove business logic behind PaletteItem from palette (aka dispatch
commands and preview tabs externally)
