eg_staged_bib_overlay: needs guard against loading new authority before matching

[gmcharlt]

eg_staged_bib_overlay has no protections against the load_new_auths action being run before the match_auths action. If that happens, the incoming authority records are unconditionally imported as new records, leading to potential duplication of authority records.

Some possible changes are:

• directly complaining if match_auths hasn't been run yet
• having the report action include counts of authority overlays