exception: add InvalidEnumString error
exception: add InvalidEnumString error

Change-Id: I138d468cc5e16241b450108eedf79c4a4c317d87
Signed-off-by: Patrick Williams <cbb7353e6d953ef360baf960c122346276c6e320@stwcx.xyz>

openbmc/sdbusplus,openbmc/sdbusplus,openbmc/sdbusplus,openbmc/sdbusplus