PostProcessSettings no longer has the Post Process Materials option

In engine version 4.17 and later the Post Process Materials node is not present. This option allowed for custom Post Process Settings. Other nodes are still present and working as intended. This issue is labeled as a regression

Versions Tested:
4.16.3 - CL: 3561208 - Issue does not occur
4.17.1 - CL: 3586342 - Issue Occurs
4.18 - CL: 3597901 - Issue Occurs

1. Create a new project (No template or starter content needed)
2. Create a new blueprint > name it "TestBP" > Open TestBP
3. Navigate to the event graph and add the "Break PostProcessSettings" node
4. In the details panel search bar type "Post"
   Result: The Post Process Materials option is not present
   Expected: The Post Process Materials option is present