E2E tests use repeated strings for test data where constants add no value (#97)

---------

Co-authored-by: Pasha Sviderski <me@psviderski.name>
Co-authored-by: Anton Ovchinnikov <anton@tonyo.info>

internal/machine/api/proxy/backend.go

@@ -2,6 +2,7 @@ package proxy
 
 import (
 	"fmt"
+
 	"github.com/psviderski/uncloud/internal/machine/api/pb"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/encoding/protowire"