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/network/src/sync/network_context/custody.rs

@@ -239,7 +239,7 @@ impl<T: BeaconChainTypes> ActiveCustodyRequest<T> {
             if let Some(wait_duration) = request.is_awaiting_download() {
                 // Note: an empty response is considered a successful response, so we may end up
                 // retrying many more times than `MAX_CUSTODY_COLUMN_DOWNLOAD_ATTEMPTS`.
-                if request.download_failures > MAX_CUSTODY_COLUMN_DOWNLOAD_ATTEMPTS {
+                if request.download_failures >= MAX_CUSTODY_COLUMN_DOWNLOAD_ATTEMPTS {
                     return Err(Error::TooManyFailures);
                 }