metropolis/test/util: move in NewEphemeralClusterCredentials from rpc

Change-Id: I41603b19a76ea91c2191b0118183957973fc9ccd
Reviewed-on: https://review.monogon.dev/c/monogon/+/1960
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/core/roleserve/BUILD.bazel b/metropolis/node/core/roleserve/BUILD.bazel
index f6d8b86..abdf8b3 100644
--- a/metropolis/node/core/roleserve/BUILD.bazel
+++ b/metropolis/node/core/roleserve/BUILD.bazel
@@ -57,9 +57,9 @@
         "//metropolis/node/core/consensus",
         "//metropolis/node/core/curator",
         "//metropolis/node/core/curator/proto/api",
-        "//metropolis/node/core/rpc",
         "//metropolis/pkg/supervisor",
         "//metropolis/proto/common",
+        "//metropolis/test/util",
         "@com_github_cenkalti_backoff_v4//:backoff",
         "@com_github_google_go_cmp//cmp",
         "@org_golang_google_grpc//:go_default_library",