fix(kotlin): remove unnecessary non-null assertion from buildTypeAnnotation call

Removed the unnecessary non-null assertion operator '!!' from the buildTypeAnnotation function calls within the OptionalParameter and RequiredParameter contexts. This ensures cleaner code by relying on the nullability handling already in place.

Author: phodal

chapi-ast-typescript/src/main/kotlin/chapi/ast/typescriptast/TypeScriptAstListener.kt

@@ -110,7 +110,7 @@ open class TypeScriptAstListener : TypeScriptParserBaseListener() {
     private fun buildOptionalParameter(paramCtx: TypeScriptParser.OptionalParameterContext): CodeProperty {
         var paramType = ""
         if (paramCtx.typeAnnotation() != null) {
-            paramType = buildTypeAnnotation(paramCtx.typeAnnotation())!!
+            paramType = buildTypeAnnotation(paramCtx.typeAnnotation())
         }
 
         return CodeProperty(
@@ -122,7 +122,7 @@ open class TypeScriptAstListener : TypeScriptParserBaseListener() {
     private fun buildRequireParameter(paramCtx: TypeScriptParser.RequiredParameterContext): CodeProperty {
         var paramType = ""
         if (paramCtx.typeAnnotation() != null) {
-            paramType = buildTypeAnnotation(paramCtx.typeAnnotation())!!
+            paramType = buildTypeAnnotation(paramCtx.typeAnnotation())
         }
 
         return CodeProperty(