:sdks:python:test-suites:tox:pycommon:dependency-check fails locally

[damccorm]

sdks/python/scripts/run_dependency_check.sh relies on a WORKSPACE environment var (set on Jenkins). This script should instead write output to a build directory, like other gradle tasks.

Imported from Jira BEAM-11774. Original Jira may contain additional context.
Reported by: bhulette.