ref/stream/manager: Fix test flake where a conn was left open on error.
ref/stream/manager: Fix test flake where a conn was left open on error.

Change-Id: Ibb262438eb02b489c3012163f8b10e6d7feb24a2

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref