Route API should allow partial fails

[jiacai2050]

Describe This Problem

Route API's requests contains multiple tables, when only one table cannot route successfully, the whole request will fail, this is very unfriendly, and we don't know which table failed, since the error message have no useful info.

2023-08-14 10:26:53.046 ERRO [proxy/src/grpc/route.rs:29] Failed to handle route, err:Rpc error, code:500, message:fail to route, err:Failure caused by others, msg:Failed to route tables by cluster, req:RouteTablesRequest { schema_name: "public", table_names: ["abc", "def"] }, err:Meta client execute failed, err:Bad response, resp code:404, msg:grpc routeTables.

Proposal

Route response should tell failed tables from successful tables

Additional Context

No response