refactor: Simplify Redis RPS extraction using let-chains in monitoring_impl.rs

- Replace nested if-let statements with let-chain pattern for Redis RPS parsing
- Update module reference from monitoring to monitoring_impl in monitoring.rs

apps/charging-engine/src/monitoring.rs

@@ -1,3 +1,3 @@
 pub mod sync;
 pub mod types;
-pub mod monitoring;
+pub mod monitoring_impl;

apps/charging-engine/src/monitoring/monitoring_impl.rs

@@ -37,13 +37,11 @@ impl crate::charging::ChargingEngine {
         let info: String = redis::cmd("INFO").query_async(&mut conn).await.unwrap_or_default();
         
         for line in info.lines() {
-            if line.starts_with("instantaneous_ops_per_sec:") {
-                if let Some(rps_str) = line.split(':').nth(1) {
-                    if let Ok(rps) = rps_str.parse::<f64>() {
-                        return Ok(rps);
-                    }
+            if line.starts_with("instantaneous_ops_per_sec:")
+                && let Some(rps_str) = line.split(':').nth(1)
+                && let Ok(rps) = rps_str.parse::<f64>() {
+                    return Ok(rps);
                 }
-            }
         }
         
         let total_commands = self.extract_metric(&info, "total_commands_processed");