macos_userdefaults: Fix 2 failures
macos_userdefaults: Fix 2 failures

Avoid a method missing error on current_value and add the missing method from the helper library that wasn't copied in

Signed-off-by: Tim Smith <764ef62106582a09ed09dfa0b6bff7c05fd7d1e4@chef.io>

juliandunn/chef,higanworks/chef,jaymzh/chef,gene1wood/chef,martinisoft/chef,mattray/chef,chef/chef,mattray/chef,martinisoft/chef,Ppjet6/chef,juliandunn/chef,martinisoft/chef,Ppjet6/chef,higanworks/chef,mattray/chef,MsysTechnologiesllc/chef,gene1wood/chef,MsysTechnologiesllc/chef,juliandunn/chef,Tensibai/chef,higanworks/chef,juliandunn/chef,Ppjet6/chef,mwrock/chef,mattray/chef,nvwls/chef,martinisoft/chef,nvwls/chef,nvwls/chef,chef/chef,mwrock/chef,gene1wood/chef,Ppjet6/chef,nvwls/chef,MsysTechnologiesllc/chef,higanworks/chef,mwrock/chef,jaymzh/chef,nvwls/chef,Ppjet6/chef,mattray/chef,chef/chef,mwrock/chef,Tensibai/chef,Ppjet6/chef,higanworks/chef,jaymzh/chef,chef/chef,Tensibai/chef,Tensibai/chef,gene1wood/chef,martinisoft/chef,MsysTechnologiesllc/chef,tomdoherty/chef,juliandunn/chef,tas50/chef-1,Tensibai/chef,tomdoherty/chef,tas50/chef-1,tomdoherty/chef,tomdoherty/chef,tas50/chef-1,tas50/chef-1,nvwls/chef,jaymzh/chef,tomdoherty/chef