update key_value.hpp in libraries/rodeos/ according to CDT

Change Description

Previous PR https://github.com/EOSIO/eos/pull/10889 for EPE 1560 could not be pushed into [develop-boxed], because abieos submodule had already been updated with my change on abieos and other new changes, so I only modify the change in libraries/rodeos/include/eosio/key_value.hpp in this PR

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EOSIO / eos

update key_value.hpp in libraries/rodeos/ according to CDT #11004