which are to be seen as sub gem roots as a workaround for detecting the
location of the "gem" root for the Atom/AtomLyIntegration GEM_MODULE targets
Removed the logic in the SettingsRegistry.cmake for reading a
"gem_module_roots" key from the gem.json file in order to determine the
root of the Atom and Atom LyIntegration sub gem modules
AtomLyIntegration gems to allow additional module roots to be checked
when determining the root directory of a GEM_MODULE target
With this change the AtomViewportDisplayInfo gem.json as it is no longer
needed.