"accountHolds" should check "isDeepFrozen" for parity with "rippled"

[RaymondSeven]

Clio’s "accountHolds" implementation checks whether a trustline is ordinarily frozen, but does not check whether it is deep-frozen.

The equivalent logic in "rippled" checks both conditions:

if (isFrozen(view, account, currency, issuer) ||
isDeepFrozen(view, account, currency, issuer))
{
return nullptr;
}

Clio’s nearby "ammAccountHolds" implementation also checks both "isFrozen" and "isDeepFrozen", which suggests the missing check in "accountHolds" is an oversight.

Current Reachability

At present, "rippled" prevents a trustline from being deep-frozen without also being ordinarily frozen. Because of that invariant, the existing "isFrozen" check normally masks this issue on current ledger state.

This issue is therefore a consistency and defensive-correctness gap rather than a currently exploitable Mainnet bug.

If the invariant changes in the future, or ledger data containing only a deep-freeze flag is processed, "accountHolds" could incorrectly return a non-zero balance.

Affected Paths

"accountHolds" is used when calculating balances and offer funding for paths including:

• "book_offers"
• Expanded "ledger" responses
• "amm_info"
• "accountFunds"

Suggested Fix

Update the freeze gate in "accountHolds":

if (isFrozen(backend, sequence, account, currency, issuer, yield) ||
isDeepFrozen(backend, sequence, account, currency, issuer, yield))
{
return false;
}

A unit test should also cover a trustline that has only "lsfLowDeepFreeze" or "lsfHighDeepFreeze" set and verify that "accountHolds" returns zero.