WireManager.delete_label only checked for Symbol("label") when scanning
the schematic s-expression list, so it silently skipped and failed to
delete global_label and hierarchical_label elements — returning False
with "No matching label found" even when a visible label existed at the
given coordinates.
Fix: collect all three label-like symbol types into a set and use `in`
instead of `==` for the type check.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>