[Bug] dubbo-maven-pluggin cannot successfully compile google.protobuf.Empty into 'void' keyword

### Pre-check

- [x] I am sure that all the content I provide is in English.

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/dubbo/issues?q=is%3Aissue) and found no similar issues.

### Apache Dubbo Component

Java SDK (apache/dubbo)

### Dubbo Version

dubbo Version:3.3.5
dubbo-maven-pluggin version:3.3.5

### Steps to reproduce this issue

issue discription : i use protobuf development style of triple protocal of dubbo 3.3.5 ,i build a new maven project to manage proto file and compiled java source code, finnally commit it to my local maven repsitory so that i can make full use of the compiled code.but when i define rpc service 'rpc xx (XXModel) returns (google.protobuf.Empty)' ,and then dubbo-maven-pluggin compile,after serval times checked it gengeate 'public xx(XXModel)' left void 'keyWord'

so it possible caused by dubbo-maven-pluggin

### What you expected to happen

the void keyword appear successfully!!!

### Anything else

_No response_

### Are you willing to submit a pull request to fix on your own?

- [ ] Yes I am willing to submit a pull request on my own!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)