Refactor refined_phone_number method; Fix format_human method

lib/decidim/helsinki_smsauth/phone_number_formatter.rb

@@ -34,7 +34,7 @@ def country_code_prefix
 
       def phone_number_parts
         @phone_number_parts ||= [].tap do |parts|
-          number = phone_number.to_s
+          number = refined_phone_number
           parts << number[0..1]
           parts << number[2..4]
           parts << number[5..-1]
@@ -45,20 +45,10 @@ def country_code_hash
         @country_code_hash ||= ::Decidim::HelsinkiSmsauth.country_code
       end
 
-      def refined_phone_number(phone_number)
+      def refined_phone_number
         country_prefix = country_code_prefix.split("+").last
         entry = phone_number.to_s
-        if entry.start_with?("00")
-          refined_phone_number(entry.gsub(/\A00/, ""))
-        elsif entry.start_with?("+")
-          refined_phone_number(entry.gsub(/\A\+/, ""))
-        elsif entry.start_with?("0")
-          entry.gsub(/\A0/, "")
-        elsif entry.match?(/\A#{country_prefix}/)
-          refined_phone_number(entry.gsub(/\A#{country_prefix}/, ""))
-        else
-          entry
-        end
+        entry.gsub(/\A((00||\+)#{country_prefix}|0)/, "")
       end
     end
   end