instance group in nacos registry always be DEFAULT_GROUP when dubbo.application.register-mode=instance or all

### Environment

* Dubbo version: 3.0.2
* Operating System version: win10
* Java version: jdk11

### Steps to reproduce this issue

instance group in nacos registry always be DEFAULT_GROUP when `dubbo.application.register-mode=all or instance` and `dubbo.registry.group=dubbo`

```yaml
dubbo:
protocol:
charset: UTF-8
server: netty4
register: true
name: tri
serialization: protostuff
port: -1
provider:
dynamic: true
version: 1.0.0
validation: true
consumer:
validation: true
version: 1.0.0
application:
name: ${spring.application.name}
compiler: javassist
register-mode: all
protocol: tri
# service-discovery:
# migration: FORCE_APPLICATION
registry:
use-as-metadata-center: false
group: dubbo
parameters:
group: dubbo
namespace: ${spring.profiles.active}
```



### Expected Result

instance group will be dubbo

No source file or test is named. Start by tracing Dubbo 3.0.2's Nacos registry handling for register-mode=all or instance and the registry group parameters; done means instance registrations use the configured dubbo group instead of DEFAULT_GROUP.

Written by the indexing model from the issue text.