clippy: next_back (#5681)

turbine/src/broadcast_stage/broadcast_utils.rs

@@ -203,7 +203,7 @@ mod tests {
                     None
                 }
             })
-            .last()
+            .next_back()
             .unwrap()
             .unwrap();
 

wen-restart/src/wen_restart.rs

@@ -3295,7 +3295,7 @@ mod tests {
             generated_record
                 .path
                 .split('-')
-                .last()
+                .next_back()
                 .unwrap()
                 .split('.')
                 .next()