feat(rust): support ability to disable boxed models in client (#17931)

* feat(client): support ability to disable boxed models

Add new additional property `avoidBoxedModels` which can be configured to avoid `Box<..>` of models.

It's very nice to have such config, because it doesn't make a lot of sense for really simple models.

* test: rollback config of existed test

samples/client/others/rust/reqwest/composed-oneof/src/models/create_state_request.rs

@@ -21,7 +21,7 @@ pub enum CreateStateRequest {
 
 impl Default for CreateStateRequest {
     fn default() -> Self {
-        Self::AType(Box::default())
+        Self::AType(Default::default())
     }
 }
 

samples/client/others/rust/reqwest/composed-oneof/src/models/custom_one_of_array_schema_inner.rs

@@ -23,7 +23,7 @@ pub enum CustomOneOfArraySchemaInner {
 
 impl Default for CustomOneOfArraySchemaInner {
     fn default() -> Self {
-        Self::AType(Box::default())
+        Self::AType(Default::default())
     }
 }
 

samples/client/others/rust/reqwest/composed-oneof/src/models/custom_one_of_schema.rs

@@ -21,7 +21,7 @@ pub enum CustomOneOfSchema {
 
 impl Default for CustomOneOfSchema {
     fn default() -> Self {
-        Self::AType(Box::default())
+        Self::AType(Default::default())
     }
 }
 

samples/client/others/rust/reqwest/composed-oneof/src/models/get_state_200_response.rs

@@ -23,7 +23,7 @@ pub enum GetState200Response {
 
 impl Default for GetState200Response {
     fn default() -> Self {
-        Self::AType(Box::default())
+        Self::AType(Default::default())
     }
 }