[bugfix] Don't return Account or Status if new and dereferencing failed, other small fixes (#2563)

* tidy up account, status, webfingering logic a wee bit

* go fmt

* invert published check

* alter resp initialization

* get Published from account in typeutils

* don't instantiate error for no darn good reason

* shadow err

* don't repeat error codes in wrapped errors

* don't wrap error unnecessarily

internal/ap/interfaces.go

@@ -163,6 +163,7 @@ type Accountable interface {
 	WithManuallyApprovesFollowers
 	WithEndpoints
 	WithTag
+	WithPublished
 }
 
 // Statusable represents the minimum activitypub interface for representing a 'status'.