fix: inaccurate Server-Timing durations

The transaction duration was notably off, doing:

```
curl localhost:3000/rpc/sleep?seconds=5 -i
```

Shows `46.1` for the `transaction;dur`, with this fix we obtain
`5007.3`.

Fixes https://github.com/PostgREST/postgrest/issues/4522

This also fixes inaccurate "schema cache queried" logs,
see https://github.com/PostgREST/postgrest/issues/4551.

src/PostgREST/Response/Performance.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE NumericUnderscores #-}
 module PostgREST.Response.Performance
   ( ServerTiming (..)
   , serverTimingHeader
@@ -24,12 +23,12 @@ data ServerTiming =
 -- The duration precision is milliseconds, per the docs
 --
 -- >>> serverTimingHeader ServerTiming { plan=Just 0.1, transaction=Just 0.2, response=Just 0.3, jwt=Just 0.4, parse=Just 0.5}
--- ("Server-Timing","jwt;dur=400.0, parse;dur=500.0, plan;dur=100.0, transaction;dur=200.0, response;dur=300.0")
+-- ("Server-Timing","jwt;dur=0.4, parse;dur=0.5, plan;dur=0.1, transaction;dur=0.2, response;dur=0.3")
 serverTimingHeader :: ServerTiming -> HTTP.Header
 serverTimingHeader timing =
   ("Server-Timing", renderTiming)
   where
-    renderMetric metric = maybe "" (\dur -> BS.concat [metric, BS.pack $ ";dur=" <> showFFloat (Just 1) (dur * 1_000) ""])
+    renderMetric metric = maybe "" (\dur -> BS.concat [metric, BS.pack $ ";dur=" <> showFFloat (Just 1) dur ""])
     renderTiming = BS.intercalate ", " $ (\(k, v) -> renderMetric k (v timing)) <$>
       [ ("jwt", jwt)
       , ("parse", parse)