net: avoid recursive m_nodes_mutex lock in DisconnectNode()

Have `CConnman::DisconnectNode()` iterate `m_nodes` itself instead of
using `FindNode()`. This avoids recursive mutex lock and drops the only
caller of `FindNode()` which used the return value for something else
than a boolean found/notfound.

Author: vasild

src/net.cpp

@@ -3631,9 +3631,11 @@ void CConnman::GetNodeStats(std::vector<CNodeStats>& vstats) const
 bool CConnman::DisconnectNode(const std::string& strNode)
 {
     LOCK(m_nodes_mutex);
-    if (CNode* pnode = FindNode(strNode)) {
-        LogDebug(BCLog::NET, "disconnect by address%s match, %s", (fLogIPs ? strprintf("=%s", strNode) : ""), pnode->DisconnectMsg(fLogIPs));
-        pnode->fDisconnect = true;
+    auto it = std::ranges::find_if(m_nodes, [&strNode](CNode* node) { return node->m_addr_name == strNode; });
+    if (it != m_nodes.end()) {
+        CNode* node{*it};
+        LogDebug(BCLog::NET, "disconnect by address%s match, %s", (fLogIPs ? strprintf("=%s", strNode) : ""), node->DisconnectMsg(fLogIPs));
+        node->fDisconnect = true;
         return true;
     }
     return false;