Repro:
Install Unity using any method: the Hub or Linux Download Assistant or unpack from Unity.tar.xz
Attempt to launch it from command line: ~/Unity-2019.1.0f2/Editor/Unity

Result is the "error while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory"

The editor is missing libgconf-2-4 package that's not installed by default. If it does not repro try `sudo apt remove libgconf-2-4`

Known workarounds:
- Install missing dependency: `sudo apt install libgconf-2-4`
- Launch the editor through the Hub

Tested on Ubuntu 18.04