test(functional): use nwaku-pr:3939 fleet (PX stale-ENR prune fix)

The light-client compat flakiness is driven by peer-exchange pollution:
the shared test fleet's PX server hands each light client the ENRs of
every other parallel cell's backends (incl. torn-down ones). The light
client churns dialing those dead peers ('all dials failed') and its
filter peer-selection intermittently can't find the connected fleet node
for the community shard ('no suitable peers found') -> missed message ->
timeout. Affects both v10.34.1 and v10.33.2 light cells, flaky.

Point the fleet (boot-1 + store) at quay.io/wakuorg/nwaku-pr:3939, the
build of logos-messaging/logos-delivery#3939 which prunes stale
Discv5-origin peers from the peer store (reconcilePeerStoreWithRoutingTable
in the discv5 search loop), so PX stops advertising dead sibling ENRs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: igor-sirotin

tests-functional/docker-compose.waku.yml

@@ -1,6 +1,6 @@
 services:
   boot-1:
-    image: wakuorg/nwaku:v0.38.1
+    image: quay.io/wakuorg/nwaku-pr:3939
     entrypoint: [
       "/usr/bin/wakunode",
       "--discv5-discovery=true",
@@ -37,7 +37,7 @@ services:
       test: ["CMD-SHELL", "curl -X GET -H 'Content-Type: application/json' http://0.0.0.0:8645 || exit 0"]
 
   store:
-    image: wakuorg/nwaku:v0.38.1
+    image: quay.io/wakuorg/nwaku-pr:3939
     # Publish the nwaku REST API (incl. Store API) on an ephemeral host port so
     # tests on the host can query it without colliding on shared CI hosts.
     # The actual host port is discovered at runtime via the Docker API