fix(rocksdb): nextValue copy paste bug

[ajw221]

Intent

• Fix RocksDB.nextValue copy paste bug matching RocksDB.nextKey

Implementation

• Updated RocksDB.nextValue to use value_serializerinstead ofkey_serializer`

Ramifications

• This bug is currently affecting several functions in Reader.zig, which rely on nextValue for processing data

Test

• Added a sanity check unit test around this fix to ensure it doesn't regress

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
src/ledger/database/interface.zig	99.73% <100.00%> (+0.01%)	⬆️
src/ledger/database/rocksdb.zig	99.34% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[Sobeston]

needs a rebase