Stop tx processing if failed to delete expired credentials (#6715)

Co-authored-by: Ed Hennis <ed@ripple.com>

include/xrpl/ledger/CredentialHelpers.h

@@ -39,16 +39,10 @@ namespace credentials {
 
 // Check if credential sfExpiration field has passed ledger's parentCloseTime
 bool
-checkExpired(
-    std::shared_ptr<SLE const> const& sleCredential,
-    NetClock::time_point const& closed);
-
-// Return true if any expired credential was found in arr (and deleted)
-bool
-removeExpired(ApplyView& view, STVector256 const& arr, beast::Journal const j);
+checkExpired(SLE const& sleCredential, NetClock::time_point const& closed);
 
 // Actually remove a credentials object from the ledger
-TER
+[[nodiscard]] TER
 deleteSLE(
     ApplyView& view,
     std::shared_ptr<SLE> const& sleCredential,