[kotlin] Fix compile error in enum properties with "" values(#18660) (#21416)

Author: chizhanov

modules/openapi-generator/src/main/resources/kotlin-client/enum_class.mustache

@@ -85,14 +85,14 @@ import kotlinx.serialization.*
     {{/multiplatform}}
     {{#isArray}}
     {{#isList}}
-    {{&name}}(listOf({{{value}}})){{^-last}},{{/-last}}{{#-last}};{{/-last}}
+    {{#name}}{{^isEmpty}}{{&name}}{{/isEmpty}}{{#isEmpty}}_{{/isEmpty}}{{/name}}(listOf({{{value}}})){{^-last}},{{/-last}}{{#-last}};{{/-last}}
     {{/isList}}
     {{^isList}}
-    {{&name}}(arrayOf({{{value}}})){{^-last}},{{/-last}}{{#-last}};{{/-last}}
+    {{#name}}{{^isEmpty}}{{&name}}{{/isEmpty}}{{#isEmpty}}_{{/isEmpty}}{{/name}}(arrayOf({{{value}}})){{^-last}},{{/-last}}{{#-last}};{{/-last}}
     {{/isList}}
     {{/isArray}}
     {{^isArray}}
-    {{&name}}({{{value}}}){{^-last}},{{/-last}}{{#-last}};{{/-last}}
+    {{#name}}{{^isEmpty}}{{&name}}{{/isEmpty}}{{#isEmpty}}_{{/isEmpty}}{{/name}}({{{value}}}){{^-last}},{{/-last}}{{#-last}};{{/-last}}
     {{/isArray}}
 {{/enumVars}}{{/allowableValues}}
     /**