fees: leftover references to `policy/fees.cpp`

[fanquake]

Pointed out here: #33218 (comment)

I still see some references to the src/policy/fees.h file removed by this PR:

$ git grep -n policy/fees.h
src/wallet/rpc/spend.cpp:206: * @param[in]     conf_target       UniValue integer; confirmation target in blocks, values between 1 and 1008 are valid per policy/fees.h;
test/functional/rpc_estimatefee.py:39:        # max value of 1008 per src/policy/fees.h
test/functional/rpc_psbt.py:604:                assert_raises_rpc_error(-8, "Invalid conf_target, must be between 1 and 1008",  # max value of 1008 per src/policy/fees.h
test/functional/wallet_basic.py:337:            assert_raises_rpc_error(-8, "Invalid conf_target, must be between 1 and 1008",  # max value of 1008 per src/policy/fees.h
test/functional/wallet_fundrawtransaction.py:851:                assert_raises_rpc_error(-8, "Invalid conf_target, must be between 1 and 1008",  # max value of 1008 per src/policy/fees.h
test/functional/wallet_send.py:315:                expect_error=(-8, "Invalid conf_target, must be between 1 and 1008"))  # max value of 1008 per src/policy/fees.h

[fanquake]

cc @ismaelsadeeq

[ismaelsadeeq]

Thanks @ryanofsky @fanquake I opened #33864 with a fix