Regression: carry field `sinceVersion` into composite types breaks other use of these types

[bjin]

Commit bca8849 carries field sinceVersion down to composite types, but it seems that this behavior change will break other use of these composite types.

Schema file: https://www.cmegroup.com/ftp/SBEFix/Production/Templates/templates_v13.xml (registration required to download, uploaded as templates_v13.xml.txt). The schema version is 13.

Composite types:

        <composite name="PRICENULL9" description="Optional Price with constant exponent -9" sinceVersion="9">
            <type name="mantissa" description="mantissa" presence="optional" nullValue="9223372036854775807" primitiveType="int64"/>
            <type name="exponent" description="exponent" presence="constant" primitiveType="int8">-9</type>
        </composite>

New fields with PRICENULL9 type:

    <ns2:message name="MDInstrumentDefinitionFX63" id="63" description="MDInstrumentDefinitionFX" blockLength="337" semanticType="d" sinceVersion="12">
        ...
        <field name="AltMinPriceIncrement" id="37739" type="PRICENULL9" description="New sub-tick which is only available for order entry when certain conditions are met, tick value which corresponds to the Alt Min Quote Life" offset="309" sinceVersion="13" semanticType="Price"/>
        <field name="AltMinQuoteLife" id="37738" type="uInt32NULL" description="MQL duration in number of microseconds applied to orders at AltMinPriceIncrement" offset="317" sinceVersion="13" semanticType="int"/>
        <field name="AltPriceIncrementConstraint" id="37742" type="PRICENULL9" description="Minimum price offset better than the best Standard Tick order for an order to be allowed into the market" offset="321" sinceVersion="13" semanticType="Price"/>
        <field name="MaxBidAskConstraint" id="37743" type="PRICENULL9" description="Maximum bid/ask spread for which sub-tick orders will be accepted (Sub tick orders will be rejected if bid/ask spread is greater than this value)" offset="329" sinceVersion="13" semanticType="Price"/>
        ...
    </ns2:message>

The new fields from MDInstrumentDefinitionFX63 promotes sinceVersion=13 down to composite type PRICENULL9, which breaks use of PRICENULL9 from other types with older acting schema version.

class PRICENULL9
{
    ...
    SBE_NODISCARD std::int64_t mantissa() const SBE_NOEXCEPT
    {
        if (m_actingVersion < 13)
        {
            return INT64_C(9223372036854775807);
        }

        std::int64_t val;
        std::memcpy(&val, m_buffer + m_offset + 0, sizeof(std::int64_t));
        return SBE_LITTLE_ENDIAN_ENCODE_64(val);
    }
    ...
};

[mjpt777]

@bjin Does this fix work for you?

[bjin]

@mjpt777 Yes, the issue is fixed. Thanks!