Remove redundant rubygem-ffi

The rubygem-ffi component was added in the agent-runtime-<version> project for
all platforms and in the _shared-agent-components on Windows, etc. Just add it
always in the _shared-agent-components, which is also included by
_shared-pe-installer-runtime.

    $ git grep rubygem-ffi configs/projects/
    configs/projects/_pdk-components.rb:proj.component 'rubygem-ffi'
    configs/projects/_shared-agent-components.rb:proj.component 'rubygem-ffi'
    configs/projects/_shared-pe-bolt-server.rb:proj.component('rubygem-ffi')
    configs/projects/_shared-pe-bolt-server_with_ruby.rb:proj.component('rubygem-ffi')
    configs/projects/_shared-pe-installer-runtime.rb:proj.component('rubygem-ffi')
    configs/projects/bolt-runtime.rb:  proj.component 'rubygem-ffi'

The only project that doesn't add the ffi rubygem is client-tools-runtime-*

configs/projects/_shared-agent-components.rb

@@ -60,10 +60,10 @@
 proj.component 'rubygem-locale'
 proj.component 'rubygem-gettext'
 proj.component 'rubygem-fast_gettext'
+proj.component 'rubygem-ffi'
 
 if platform.is_windows? || platform.is_solaris?
   proj.component 'rubygem-minitar'
-  proj.component 'rubygem-ffi'
 end
 
 if platform.is_macos?

configs/projects/agent-runtime-7.x.rb

@@ -54,7 +54,6 @@
   # When adding components to this list, please
   # add them to pe-installer-runtime-main as well
   proj.component 'rubygem-concurrent-ruby'
-  proj.component 'rubygem-ffi'
   proj.component 'rubygem-multi_json'
   proj.component 'rubygem-optimist'
   proj.component 'rubygem-highline'

configs/projects/agent-runtime-main.rb

@@ -56,7 +56,6 @@
   # When adding components to this list, please
   # add them to pe-installer-runtime-main as well
   proj.component 'rubygem-concurrent-ruby'
-  proj.component 'rubygem-ffi'
   proj.component 'rubygem-multi_json'
   proj.component 'rubygem-optimist'
   proj.component 'rubygem-highline'