ServerReflectionImplSpec: The Server Reflection implementation should retrieve server reflection info flaky

Likely 150ms is just a bit tight for CI:

```
[info] The Server Reflection implementation
[info] - should retrieve server reflection info *** FAILED *** (450 milliseconds)
[info] A timeout occurred waiting for a future to complete. Waited 150 milliseconds. (ServerReflectionImplSpec.scala:54)
[info] org.scalatest.concurrent.ScalaFutures$$anon$1$$anon$2:
[info] at org.scalatest.concurrent.ScalaFutures$$anon$1.futureValueImpl(ScalaFutures.scala:339)
[info] at org.scalatest.concurrent.Futures$FutureConcept.futureValue(Futures.scala:476)
[info] at org.scalatest.concurrent.Futures$FutureConcept.futureValue$(Futures.scala:475)
[info] at org.scalatest.concurrent.ScalaFutures$$anon$1.futureValue(ScalaFutures.scala:281)
[info] at org.apache.pekko.grpc.internal.ServerReflectionImplSpec.$anonfun$new$5(ServerReflectionImplSpec.scala:54)
```

Open ServerReflectionImplSpec.scala and inspect the futureValue timeout at line 54, then run the focused spec to reproduce the intermittent failure. Confirm the test remains reliable in CI with a timeout appropriate for the server reflection response, and verify the spec passes consistently.

Written by the indexing model from the issue text.