docs(dash): correct fully_verified_count doc on verify_rotated_quorums == false path

The comment claimed `fully_verified_count` is always `0` when `verify_rotated_quorums == false`, but the else branch at the `feed_qr_info` storage step counts every entry of `qualified_last_commitment_per_index` whose `.verified` is `Verified`. Cache hits returned by `known_qualified_quorum_entry` retain their prior `Verified` status (the gate only stores fully-Verified cycles), so the count can be non-zero even with verification disabled. Update the doc to describe the actual behavior.

Addresses CodeRabbit review comment on PR #736
#736 (comment)

Author: xdustinface

dash/src/sml/masternode_list_engine/mod.rs

@@ -80,9 +80,11 @@ pub struct QRInfoFeedResult {
     /// distinguish cache-hit observability from a trust signal.
     pub newly_qualified_count: usize,
     /// Rotated quorums whose `.verified` is `LLMQEntryVerificationStatus::Verified`
-    /// after this call settled. Always `0` when `verify_rotated_quorums == false`.
-    /// A cycle is only stored in `rotated_quorums_per_cycle` when every entry is
-    /// `Verified`.
+    /// after this call settled. May be non-zero even when
+    /// `verify_rotated_quorums == false` because cached entries returned by
+    /// `known_qualified_quorum_entry` retain their prior `Verified` status.
+    /// A cycle is only stored in `rotated_quorums_per_cycle` when every entry
+    /// is `Verified`.
     pub fully_verified_count: usize,
     /// Height of the cycle from `last_commitment_per_index` if (and only if)
     /// the storage gate fired and the cycle was inserted into