sync: fix KZG batch verifier deadlock on timeout (#16141)

`validateWithKzgBatchVerifier` could timeout (12s) and once it times out
because `resChan` is unbuffered, the verifier will stuck at following
line at `verifyKzgBatch` as its waiting for someone to grab the result
from `resChan`:
```
	for _, verifier := range kzgBatch {
		verifier.resChan <- verificationErr
	}
```
Fix is to make kzg batch verification non blocking on timeouts by
buffering each request’s buffered size 1

changelog/fix_kzg_batch_verifier_timeout_deadlock.md

@@ -0,0 +1,3 @@
+### Fixed
+
+- Fix deadlock in data column gossip KZG batch verification when a caller times out preventing result delivery.