Keep STALE on Contacts while a poll is in flight

A poll that returned the same stale snapshot dropped STALE from the
Contacts cohort until the next answer, because the in-flight loading flag
outranked stale and the source revision ignored the provider name. A
source that has answered now reads its status without the loading flag;
one that has never answered (AIS first connect) still reads as loading,
so it shows no STALE before any snapshot exists.

src/ui/cockpitContext.test.mjs

@@ -167,8 +167,6 @@ test('a snapshot fills the card and keeps classes other code sets', async (t) =>
 });
 
 test('each count names the provider its snapshot reports, with its feed state', async (t) => {
-  // HAL-721: the counters named fixed providers while the layer and the
-  // Contacts list named the one that answered.
   const reported = snapshot();
   reported.cohorts[0].source = 'adsb.lol';
   reported.cohorts[0].sourceStatus = 'fallback';