Fix checking ammID field of account

[oleks-rip]

High Level Overview of Change

This fix add check for sfAMMID field in amm_info handler.

Context of Change

Without this check debug version of rippled crash on assert in ledger::read()
Bug was found during automation testing.

Type of Change

• Bug fix (non-breaking change which fixes an issue)

API Impact

• Public API: amm_info will not crash debug version of the rippled

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.9%. Comparing base (838978b) to head (a9f6586).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #5188     +/-   ##
=========================================
- Coverage     77.9%   77.9%   -0.0%     
=========================================
  Files          782     782             
  Lines        66621   66622      +1     
  Branches      8161    8158      -3     
=========================================
- Hits         51902   51874     -28     
- Misses       14719   14748     +29     

Files with missing lines	Coverage Δ
src/xrpld/rpc/handlers/AMMInfo.cpp	92.6% <100.0%> (+0.1%)	⬆️

... and 8 files with indirect coverage changes

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[gregtatcam]

👍 LGTM

[shawnxie999]

Unrelated to this change, but on line 162, an non existent AMM object is returned with rpcACT_NOT_FOUND error. Doesn't sound right, should we fix it?

        auto const amm = ledger->read(ammKeylet);
        if (!amm)
            return Unexpected(rpcACT_NOT_FOUND);

[shawnxie999]

nit: the test could be moved into testErrors() IMO

[gregtatcam]

Unrelated to this change, but on line 162, an non existent AMM object is returned with rpcACT_NOT_FOUND error. Doesn't sound right, should we fix it?

        auto const amm = ledger->read(ammKeylet);
        if (!amm)
            return Unexpected(rpcACT_NOT_FOUND);

It's half correct since AMM might be fetched by amm account. But correct, rpcOBJECT_NOT_FOUND is probably more appropriate.

[shawnxie999]

Unrelated to this change, but on line 162, an non existent AMM object is returned with rpcACT_NOT_FOUND error. Doesn't sound right, should we fix it?

        auto const amm = ledger->read(ammKeylet);
        if (!amm)
            return Unexpected(rpcACT_NOT_FOUND);

It's half correct since AMM might be fetched by amm account. But correct, rpcOBJECT_NOT_FOUND is probably more appropriate.

although i believe we may need a new API version for this change

[oleks-rip]

Ready to be merged.