URL Encode Scan Policy name when editing policy

Summary

Steps to reproduce

1. Create Project_A and add file .gitlab/security-policies/policy.yml:

type: scan_result_policy
name: example/example
description: Example
enabled: true
rules:
  - type: scan_finding
    branches: []
    scanners: []
    vulnerabilities_allowed: 0
    severity_levels:
      - critical
    vulnerability_states:
      - newly_detected
actions:
  - type: require_approval
    approvals_required: 1
    group_approver_ids:
      - 5551212

2. Create Project_B and set Project A using Edit policy project
3. Refresh the Policies page to see the now-applied policies
4. Click on example-org/example
5. Click Edit Policy
6. Get a 404 when the Edit URL includes example-org/example, which is interpreted as part of the path:
7. https://gitlab.example.com/project_b/-/security/policies/example/example/edit?environment_id=-1&type=scan_result_policy

Example Project

What is the current bug behavior?

404

What is the expected correct behavior?

Policy editor

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes