[RUST-AXUM] fix generator not handling application/x-www-form-urlencoded request content, update for initial fix #18061 (#18362)

* fix OpenAPITools/openapi-generator#18060

* isolate the option as separate flag

* apply modification suggested by @wing328

* remove added newlines

* do not change the handle of multipart body, keep the change only for x-www-form-urlencoded

bin/configs/manual/rust-axum-petstore-with-fake-endpoints-models-for-testing.yaml

@@ -7,4 +7,6 @@ additionalProperties:
   hideGenerationTimestamp: "true"
   packageName: petstore-with-fake-endpoints-models-for-testing
   publishRustRegistry: crates-io
-enablePostProcessFile: true
+globalProperties:
+  skipFormModel: false
+enablePostProcessFile: true

bin/configs/manual/rust-axum-petstore.yaml

@@ -6,4 +6,6 @@ generateAliasAsModel: true
 additionalProperties:
   hideGenerationTimestamp: "true"
   packageName: petstore
+globalProperties:
+  skipFormModel: false
 enablePostProcessFile: true

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

@@ -52,6 +52,7 @@ import org.openapitools.codegen.api.TemplatingEngineAdapter;
 import org.openapitools.codegen.config.GlobalSettings;
 import org.openapitools.codegen.examples.ExampleGenerator;
 import org.openapitools.codegen.languages.PhpNextgenClientCodegen;
+import org.openapitools.codegen.languages.RustAxumServerCodegen;
 import org.openapitools.codegen.languages.RustServerCodegen;
 import org.openapitools.codegen.meta.FeatureSet;
 import org.openapitools.codegen.meta.GeneratorMetadata;
@@ -4742,7 +4743,7 @@ public class DefaultCodegen implements CodegenConfig {
                 contentType = contentType.toLowerCase(Locale.ROOT);
             }
             if (contentType != null &&
-                    (contentType.startsWith("application/x-www-form-urlencoded") ||
+                    ((!(this instanceof RustAxumServerCodegen) && contentType.startsWith("application/x-www-form-urlencoded")) ||
                             contentType.startsWith("multipart"))) {
                 // process form parameters
                 formParams = fromRequestBodyToFormParameters(requestBody, imports);