doAsUserId parameter removed from URL when links to pages belonging to other sites of the portal

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.X EE, 7.0.X, 7.1.X, Master
• Fix Version/s: 6.2.X EE, 7.0.0 DXP FP69, 7.0.X, 7.1.10 DXP FP4, 7.1.10.1 SP1, 7.1.2 CE GA3, 7.1.X, Master
• Component/s: Core Infrastructure, User Management
• Labels:
  • backend_test
  • ee-ts
  • liferay-dxp-70-sp10
  • liferay-dxp-71-sp1
  • liferay-fixpack-de-69-7010
  • liferay-fixpack-dxp-4-7110
• Branch Version/s:
  7.1.x, 7.0.x, 6.2.x
• Backported to Branch:
  Committed
• Story Points: 0.25
• Fix Priority: 3
• Sprint: U&SM | Sprint 5
• Git Pull Request: https://github.com/hhuijser/liferay-portal/pull/3398

Reproduction Steps:

1. Create a new site "new site" and a public page "test"
2. Go back to default Liferay site and create a new public page "new test" (Type: Link to URL, URL: /web/new-site/test)
3. Create a new user and assign the user members of Liferay and "new site"
4. Go to Control Panel > Users and Organizations 
5. Besides the new user's record, click Actions > Impersonate User
6. Click on "new test" page which redirects to localhost:8080/web/new-site/test

Actual Result: doAsUserId parameter is removed from URL "localhost:8080/web/new-site/test" so the impersonation is not working.
Expected Result: Impersonation is working as the URL is within Liferay portal.

Reproduced in:
master (457e233b6dedd867edc023c31b8b80ab8ad02b04)
7.0.x (174354bc4b1cff5eaa5f202b67ee277c568bc6ff)
ee-6.2.x (909e05f1db5afac3d4a8f7d8a2e0760866e3a58b)