FFM-12192 MetricsEvent logger nil check

lib/ff/ruby/server/sdk/api/metrics_event.rb

@@ -21,7 +21,11 @@ def eql?(other)
     # project sizes. Issue being tracked in FFM-12192, and once resolved, can feasibly remove
     # these checks in a future release.
     unless other.is_a?(MetricsEvent)
-      @logger.warn("Warning: Attempted to compare MetricsEvent with #{other.class.name}" )
+      # We should always have a logger available except when we've deep cloned this class.  We don't do any
+      # equality check on clones in metrics code anyway, so this is just a safety check.
+      if @logger
+        @logger.warn("Warning: Attempted to compare MetricsEvent with #{other.class.name}")
+      end
       return false
     end
 
@@ -42,7 +46,7 @@ def marshal_dump
 
   def marshal_load(array)
     @feature_config, @target, @variation = array
-    @logger = nil  
+    @logger = nil
   end