Enforce stricter checks on certain constants (#8500)

Which issue # does this PR address?
None


  All of these are performing a check, and adding a batch, or creating a new lookup, or a new query, etc..
Hence all of these limits would be off by one.

Example:

```rust
// BACKFILL_BATCH_BUFFER_SIZE = 5
if self.batches.iter().filter(...).count() >= BACKFILL_BATCH_BUFFER_SIZE {
return None;  // ← REJECT
}
// ... later adds batch via Entry::Vacant(entry).insert(...)
```

Without the `>` being changed to a `>=` , we would allow 6. The same idea applies to all changes proposed.


Co-Authored-By: Antoine James <antoine@ethereum.org>

Co-Authored-By: Jimmy Chen <jimmy@sigmaprime.io>

Co-Authored-By: Jimmy Chen <jchen.tc@gmail.com>

beacon_node/lighthouse_network/src/discovery/mod.rs

@@ -674,7 +674,7 @@ impl<E: EthSpec> Discovery<E> {
     /// updates the min_ttl field.
     fn add_subnet_query(&mut self, subnet: Subnet, min_ttl: Option<Instant>, retries: usize) {
         // remove the entry and complete the query if greater than the maximum search count
-        if retries > MAX_DISCOVERY_RETRY {
+        if retries >= MAX_DISCOVERY_RETRY {
             debug!("Subnet peer discovery did not find sufficient peers. Reached max retry limit");
             return;
         }