set disallowAdditionalPropertiesIfNotPresent to false as default

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java

@@ -233,7 +233,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
 
         ImmutableMap.Builder<String, String> frameworkBuilder = new ImmutableMap.Builder<>();
         for (FrameworkStrategy frameworkStrategy : frameworkStrategies) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpReducedClientCodegen.java

@@ -194,7 +194,7 @@ public class CSharpReducedClientCodegen extends AbstractCSharpCodegen {
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
 
         ImmutableMap.Builder<String, String> frameworkBuilder = new ImmutableMap.Builder<>();
         for (FrameworkStrategy frameworkStrategy : frameworkStrategies) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java

@@ -136,7 +136,7 @@ public class GoClientCodegen extends AbstractGoCodegen {
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
     }
 
     /**

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java

@@ -568,7 +568,7 @@ public class PowerShellClientCodegen extends DefaultCodegen implements CodegenCo
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
 
         // default value in the template
         additionalProperties.put("powershellVersion", "6.2"); // minimal PS version

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java

@@ -184,7 +184,7 @@ public class PythonClientCodegen extends AbstractPythonCodegen implements Codege
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
     }
 
     @Override

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java

@@ -233,7 +233,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
                 "Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
-        this.setDisallowAdditionalPropertiesIfNotPresent(true);
+        this.setDisallowAdditionalPropertiesIfNotPresent(false);
 
     }