refactor: Move checkDestinationAndTag onto AccountRootEntry

Replace the entry-taking checkDestinationAndTag free function with the
const member AccountRootEntry::checkDestinationAndTag(hasDestinationTag).
The body is short, so it is inline in the header.

include/xrpl/ledger/entries/AccountRootEntry.h

@@ -120,6 +120,26 @@ public:
     [[nodiscard]] bool
     isPseudoAccount() const;
 
+    /**
+     * Checks the destination and tag.
+     *
+     * - Checks that the entry exists.
+     * - If the entry requires a destination tag, checks that there is a tag.
+     */
+    [[nodiscard]] TER
+    checkDestinationAndTag(bool hasDestinationTag) const
+    {
+        if (!this->exists())
+            return tecNO_DST;
+
+        // The tag is basically account-specific information we don't
+        // understand, but we can require someone to fill it in.
+        if ((*this)->isFlag(lsfRequireDestTag) && !hasDestinationTag)
+            return tecDST_TAG_NEEDED;  // Cannot send without a tag
+
+        return tesSUCCESS;
+    }
+
     /**
      * Increase owner-count fields when the caller supplies the sponsor.
      *

include/xrpl/ledger/helpers/AccountRootHelpers.h

@@ -9,7 +9,6 @@
 #include <xrpl/protocol/Rate.h>
 #include <xrpl/protocol/SField.h>
 #include <xrpl/protocol/STLedgerEntry.h>
-#include <xrpl/protocol/TER.h>
 #include <xrpl/protocol/XRPAmount.h>
 
 #include <cstdint>
@@ -261,13 +260,4 @@ isPseudoAccount(ReadView const& view, AccountID const& accountId)
     return AccountRootEntryR(accountId, view).isPseudoAccount();
 }
 
-/**
- * Checks the destination and tag.
- *
- * - Checks that the SLE is not null.
- * - If the SLE requires a destination tag, checks that there is a tag.
- */
-[[nodiscard]] TER
-checkDestinationAndTag(AccountRootEntryR const& toSle, bool hasDestinationTag);
-
 }  // namespace xrpl

src/libxrpl/ledger/View.cpp

@@ -10,7 +10,6 @@
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/ledger/entries/AccountRootEntry.h>
-#include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/CredentialHelpers.h>
 #include <xrpl/ledger/helpers/DirectoryHelpers.h>
 #include <xrpl/ledger/helpers/MPTokenHelpers.h>
@@ -472,7 +471,7 @@ canWithdraw(
     bool hasDestinationTag,
     std::optional<std::vector<UInt256>> const& credentialIDs)
 {
-    if (auto const ret = checkDestinationAndTag(toSle, hasDestinationTag))
+    if (auto const ret = toSle.checkDestinationAndTag(hasDestinationTag))
         return ret;
 
     if (from == to)

src/libxrpl/ledger/helpers/AccountRootHelpers.cpp

@@ -16,7 +16,6 @@
 #include <xrpl/protocol/Rate.h>
 #include <xrpl/protocol/SField.h>
 #include <xrpl/protocol/STLedgerEntry.h>
-#include <xrpl/protocol/TER.h>
 #include <xrpl/protocol/XRPAmount.h>
 #include <xrpl/protocol/digest.h>
 
@@ -263,18 +262,4 @@ getPseudoAccountFields()
     return kPseudoFields;
 }
 
-[[nodiscard]] TER
-checkDestinationAndTag(AccountRootEntryR const& toSle, bool hasDestinationTag)
-{
-    if (!toSle.exists())
-        return tecNO_DST;
-
-    // The tag is basically account-specific information we don't
-    // understand, but we can require someone to fill it in.
-    if (toSle->isFlag(lsfRequireDestTag) && !hasDestinationTag)
-        return tecDST_TAG_NEEDED;  // Cannot send without a tag
-
-    return tesSUCCESS;
-}
-
 }  // namespace xrpl