Nexus 3 migration not using UI request timeout setting

Nexus 3 upgrade from Nexus 2 is not using the UI request timeout setting that was introduced by NEXUS-12033.

If Nexus 2.x has a large number of repositories (in this case 800+), it can take more than 60 seconds to for Nexus 3 to receive and list the repositories. Even though the UI request time is set to 1800 seconds in Nexus 3, the UI times out after 60 seconds during the listing of repositories in that upgrade step.

Steps to reproduce:

1) Use a Nexus 2.x instance with large number of repos and enable upgrade capability.

2) Set up Nexus 3.14.0

• set the http proxy config to point to charles proxy. 
• set UI request timeout to 1800 seconds
• enable upgrade capability 

3) Start upgrade in Nexus 3

4) During listing of repositories in the upgrade step, enable throttling on charles proxy.

5) You will get a UI timeout in Nexus 3 after 60 seconds

Expected Behavior

UI timeout should not occur until it reaches the UI timeout that was configured in Nexus 3.