Remove 'nil' from array before returning (fastlane#21772)

Fixes fastlane#21768 when there is no device match for a given name.

scan/lib/scan/detect_values.rb

@@ -217,7 +217,7 @@ def self.detect_simulator(devices, requested_os_type, deployment_target_key, def
             if pieces.count == 0
               [] # empty array
             elsif pieces.count == 1
-              [ highest_compatible_simulator(simulators, pieces.first) ]
+              [ highest_compatible_simulator(simulators, pieces.first) ].compact
             else # pieces.count == 2 -- mathematically, because of the 'end of line' part of our regular expression
               version = pieces[1].tr('()', '')
               display_device = "'#{pieces[0]}' with version #{version}"