Fix the analysis issues

Author: atoka93

openapi-generator-annotations/test/openapi_generator_annotations_test.dart

@@ -1,4 +1,3 @@
-import 'package:openapi_generator_annotations/openapi_generator_annotations.dart';
 import 'package:test/test.dart';
 
 void main() {

openapi-generator-cli/bin/main.dart

@@ -12,7 +12,7 @@ void main(List<String> arguments) async {
 
   var commands = [
     '-jar',
-    "${"${binPath}"}",
+    "${"$binPath"}",
     ...arguments,
   ];
   if (JAVA_OPTS.isNotEmpty) {

openapi-generator/lib/src/openapi_generator_runner.dart

@@ -76,7 +76,7 @@ class OpenapiGenerator extends GeneratorForAnnotation<annots.Openapi> {
 
       var arguments = [
         '-jar',
-        "${"${binPath}"}",
+        "${"$binPath"}",
         ...command.split(separator).toList(),
       ];
       if (JAVA_OPTS.isNotEmpty) {