add some default strings and fix test

Author: Picazsoo

samples/server/petstore/kotlin-springboot-x-kotlin-implements/src/main/kotlin/org/openapitools/model/Cat.kt

@@ -50,10 +50,10 @@ data class Cat(
     override val category: Category? = null,
 
     @get:JsonProperty("nonRequiredWithDefaultList", required = false)
-    override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf(),
+    override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf("just some default string","another default string"),
 
     @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",

samples/server/petstore/kotlin-springboot-x-kotlin-implements/src/main/kotlin/org/openapitools/model/Dog.kt

@@ -54,10 +54,10 @@ data class Dog(
     override val category: Category? = null,
 
     @get:JsonProperty("nonRequiredWithDefaultList", required = false)
-    override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf(),
+    override val nonRequiredWithDefaultList: kotlin.collections.List<kotlin.String> = arrayListOf("just some default string","another default string"),
 
     @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",