CI: bsim workflow: Fix getting bsim revision

As the bsim repo is disabled by default, west list bsim -f {sha}
fails.
Instead get the revision field which works.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

.github/workflows/bsim-tests.yaml

@@ -116,7 +116,7 @@ jobs:
           || steps.check-networking-files.outputs.any_changed == 'true'
           || steps.check-common-files.outputs.any_changed == 'true'
         run: |
-          export BSIM_VERSION=$( west list bsim -f {sha} )
+          export BSIM_VERSION=$( west list bsim -f {revision} )
           echo "Manifest points to bsim sha $BSIM_VERSION"
           cd /opt/bsim_west/bsim
           git fetch -n origin ${BSIM_VERSION}