add some default strings and fix test

Author: Picazsoo

modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java

@@ -1093,9 +1093,9 @@ public void generateModelWithRequiredFalseWithDefaults() throws Exception {
                 "@get:JsonProperty(\"category\", required = false)",
                 "override val category: Category? = null", // without default (fallback) value is nullable
                 "@get:JsonProperty(\"nonRequiredWithDefaultList\", required = false)",
-                "override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf()", // elsewhere with default (fallback) value is not nullable
+                "override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf(\"just some default string\",\"another default string\"),", // elsewhere with default (fallback) value is not nullable
                 "@get:JsonProperty(\"nonRequiredWithDefaultSet\", required = false)",
-                "override val nonRequiredWithDefaultSet: kotlin.collections.Set<kotlin.String> = setOf()",
+                "override val nonRequiredWithDefaultSet: kotlin.collections.Set<kotlin.String> = setOf(\"more strings\",\"look, it's a string!\")",
                 "@get:JsonProperty(\"nonRequiredWithDefaultString\", required = false)",
                 "override val nonRequiredWithDefaultString: kotlin.String = \"defaultValue\"",
                 "@get:JsonProperty(\"nonRequiredWithDefaultInt\", required = false)",

modules/openapi-generator/src/test/resources/3_0/kotlin/petstore-with-x-kotlin-implements.yaml

@@ -527,13 +527,13 @@ components:
           type: array
           items:
             type: string
-          default: [ ]
+          default: [ "just some default string", "another default string" ]
         nonRequiredWithDefaultSet:
           type: array
           items:
                 type: string
           uniqueItems: true
-          default: [ ]
+          default: [ "more strings", "look, it's a string!" ]
         nonRequiredWithDefaultString:
           type: string
           default: defaultValue