server: object: add 'action::emit_no_signals'
server: object: add 'action::emit_no_signals'

In a future commit we're going to change the behavior of the destructor
to always emit signals when 'action::defer_emit' is chosen so we need a
placeholder enum to clearly indicate that no signals should ever be
emitted.  Add it now, but keep the same behavior as
'action::defer_emit'.

Change-Id: I606c7739041667186f6141548a377adf91ff5518
Signed-off-by: Patrick Williams <cbb7353e6d953ef360baf960c122346276c6e320@stwcx.xyz>

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