fix: use Go 1.25 for dashboard builder step

The build-dashboard-image step had golang-cross:1.24-bookworm
hardcoded while the goreleaser step uses 1.25-bullseye.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: buger

.github/workflows/release.yml

@@ -713,7 +713,7 @@ jobs:
             -e GOMODCACHE=/go/pkg/mod \
             -v /tmp/build-dashboard.sh:/tmp/build-dashboard.sh \
             -w /go/src/github.com/TykTechnologies/tyk-analytics \
-            tykio/golang-cross:1.24-bookworm /tmp/build-dashboard.sh
+            tykio/golang-cross:1.25-bullseye /tmp/build-dashboard.sh
 
           echo "✅ Packages built successfully for $GOARCH"
       - name: Detect platform for Docker build