acts@15.0.0

The upstream package that introduces acts@15.0.0 also makes a bunch of other changes that depend on https://github.com/spack/spack/pull/24858 which is not in the current SPACK_VERSION. We probably want to upgrade to spack v0.17 a68abc15c5b1b8266130f765d1bee6290e71fa7c in a separate MR to pick up that functionality.

NOTES:

• Do NOT merge without changing the juggler branch back to master

spack.yaml

 spack:
   specs:
-    - acts@14.1.0 +dd4hep +digitization +identification +json +tgeo +ipo +examples +fatras +geant4
+    - acts@15.1.0 +dd4hep +digitization +identification +json +tgeo +ipo +examples +fatras +geant4
     - cairo@1.16.0 +fc+ft+X+pdf+gobject
     - clhep@2.4.4.0 cxxstd=17
     - cmake@3.20.0