refactor: re-generate go grpc protobuf

[daviderli614]

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Refer to a related PR or issue link (optional)

#137 、#114

What's changed and what's your intention?

This change add the --go-grpc_out parameter to generate proto command to ensure proper generation of gRPC service code (*_grpc.pb.go) for proto files containing service definitions.

protoc -I=${PROTO_ROOT} \
       --go-grpc_out=paths=source_relative:${GO_OUTPUT} \
       $(find ./proto/ -type f -iname "*.proto")

Remove unused grpc methods:

• go/greptime/v1/meta/route_grpc.pb.go
• go/greptime/v1/meta/ddl_grpc.pb.go

Checklist

• I have written the necessary comments.
• I have added the necessary unit tests and integration tests.