Resolve "FF hadron magnet vacuum"

(cherry picked from commit ae18f57d)

athena.xml

@@ -90,6 +90,9 @@
   <include ref="ip6/forward_ion_beamline.xml"/>
   <include ref="ip6/beampipe_hadron_B0.xml" />
   <include ref="ip6/beampipe.xml" />
+  <include ref="ip6/inner_vacuum_FF_magnets.xml"/>
+
+
 
   <documentation level="5">
      ## Main magnet

compact/definitions.xml

@@ -243,6 +243,7 @@ The unused IDs below are saved for future use.
     <comment> TODO naming consistency </comment>
     <constant name="ffi_ZDC_ECAL_ID"                 value="163"/>
     <constant name="ffi_ZDC_HCAL_ID"                 value="164"/>
+    <constant name="VacuumMagnetElement_1_ID"        value="165"/>
 
     <documentation> 
       #### (170-189) Forward Beamline Magnets