FE: Update empty states for policies list

Why are we doing this work

• Currently the no environment empty state shows when an environment is not set up
• Scan execution policies do not require an environment to be created

Relevant links

Non-functional requirements

• Testing:

Implementation plan

• remove no environment empty state on loading Security & Compliance => Policies
• on clicking New Policy, show no environment empty state for Network policies
• implement the empty state for an empty policies list
• implement the no results from filter empty state for an empty, filtered, policies list