[Bug report]gcli and oauth authenticator

### Version

main branch

### Describe what's wrong

Hello - I can't get gravitino cli working with oauth- no matter how I set parameters I keep on getting the following error:
```shell
Cannot invoke "org.apache.gravitino.cli.OAuthData.getServerURI()" because "oauth" is null
```
The connection seems to be working:
```shell
./gcli.sh --server

Apache Gravitino 0.9.1
```
I tried a few images from docker hub but alway get the same error as above. Do you have any idea what can be the issue here:
```shell
# Default target
#metalake=metalake
URL=http://localhost:8090
ignore=true

I also tried a couple combinations of config options:

# OAuth (Keycloak) — client_credentials using your confidential client
auth=oauth
serverURI=http://localhost:8080/realms/gravitino/protocol/openid-connect/token
#credential=gravitino-client:gravitino-secret
token=eyJhbG_8K8OemA
# scope is optional for client_credentials
scope=openid

```

### Error message and/or stacktrace

Cannot invoke "org.apache.gravitino.cli.OAuthData.getServerURI()" because "oauth" is null

### How to reproduce

```shell
Cannot invoke "org.apache.gravitino.cli.OAuthData.getServerURI()" because "oauth" is null
```
The connection seems to be working:
```shell
./gcli.sh --server

Apache Gravitino 0.9.1
```

### Additional context

_No response_