proxy: use querier cache for user info (#5532)

pkg/grpc/databroker/databroker.go

@@ -3,14 +3,12 @@ package databroker
 
 import (
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
 
 	"google.golang.org/grpc/codes"
 	status "google.golang.org/grpc/status"
-	"google.golang.org/protobuf/encoding/protojson"
 	"google.golang.org/protobuf/proto"
 	structpb "google.golang.org/protobuf/types/known/structpb"
 
@@ -53,34 +51,6 @@ func Get(ctx context.Context, client DataBrokerServiceClient, object recordObjec
 	return res.GetRecord().GetData().UnmarshalTo(object)
 }
 
-// GetViaJSON gets a record from the databroker, marshals it to JSON, and then unmarshals it to the given type.
-func GetViaJSON[T any](ctx context.Context, client DataBrokerServiceClient, recordType, recordID string) (*T, error) {
-	res, err := client.Get(ctx, &GetRequest{
-		Type: recordType,
-		Id:   recordID,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	msg, err := res.GetRecord().GetData().UnmarshalNew()
-	if err != nil {
-		return nil, err
-	}
-
-	bs, err := protojson.Marshal(msg)
-	if err != nil {
-		return nil, err
-	}
-
-	var obj T
-	err = json.Unmarshal(bs, &obj)
-	if err != nil {
-		return nil, err
-	}
-	return &obj, nil
-}
-
 // Put puts a record into the databroker.
 func Put(ctx context.Context, client DataBrokerServiceClient, objects ...recordObject) (*PutResponse, error) {
 	records := make([]*Record, len(objects))