Provide per topic validation queue size configuration

[masih]

The PubSub validation queue has a fixed size of 32 and is not configurable per topic. When high-volume topics (such as F3 GPBFT) generate excessive traffic, they overwhelm this shared queue, causing hundreds of messages per second to be rejected with "queue full" errors. This degrades overall gossipsub performance, reducing mesh sizes below optimal levels for all topics on the network.

The validation queue should be configurable per topic to prevent high-traffic topics from impacting the performance of other topics in the network.

[MarcoPolo]

agreed. I would also like the ability to set different parameters per topic as well