CmdPal: Gate TopLevelViewModel check behind SupportsPinning

Move the SupportsPinning check before the commandItem.Model.Unsafe type
test so the more expensive field access is skipped entirely for the
common non-pinning case. No functional change; pure guard ordering
improvement.

Co-authored-by: michaeljolley <[email protected]>
Agent-Logs-Url: https://github.com/microsoft/PowerToys/sessions/1ba17881-0a38-4f65-acc6-b7394a3c8de8