Remove network policies feature from the UI

What does this MR do and why?

Remove network policies feature from the UI because it is being deprecated

• remove network policies from the policies list
• remove network policy option from the new policy editor
• update tests (including e2e)

Changelog: removed

EE: true

What does this MR NOT do and why?

It does NOT delete all the underlying components (e.g. now-unused network policy drawer/editor code) because doing that in this MR would make this MR >2000lns long. This MR only ensures that a user can not get to any of the network policy paths. All the underlying components will be deleted iteratively in follow-up MRs (coming immediately after this gets merged), but there are just so many that it will be easier to delete this first.

Screenshots or screen recordings

Page	Before	After
Policy List
New Policy Editor
New Policy Editor v2

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Upload a GitLab Ultimate license
2. Navigate to a project => Security & Compliance => Policies
3. Verify the
4. Verify any Network policies do not show up in the list
5. Verify a user can not sort the policies by Network
6. Click New Policy button
7. Ensure one cannot create a Network Policy

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #352285 (closed)