Delete apex-client from packaging

Delete apex-client from packaging

The "stage-release" failed due to:
  18:51:12 [ERROR] Failed to execute goal
  org.apache.maven.plugins:maven-dependency-plugin:3.1.1:copy
  (copy-fat-jars) on project apex-pdp-package-full: Unable to
  find/resolve artifact. Could not find artifact
  org.onap.policy.apex-pdp.client:apex-client-full:jar:full:2.4.1
  in release-mirror (https://nexus.onap.org/content/repositories/public/)
  -> [Help 1]

Removed it from the package, as it is no longer part of apex-pdp.

Issue-ID: POLICY-2789
Change-Id: I4089096ab9668af33e885c70e140ce8fc1f51939
Signed-off-by: Jim Hahn <jrh3@att.com>