CDRIVER-4172 use perf.send for sending performance test results

Author: rcsanchez97

.evergreen/benchmark.yml

@@ -173,7 +173,7 @@ functions:
       file_location: mongo-c-driver/report.json
 
   "send dashboard data" :
-    command: json.send
+    command: perf.send
     params:
       name: perf
       file: mongo-c-driver/results.json
@@ -286,4 +286,4 @@ buildvariants:
     <<: *benchmark_common
   run_on:
      - centos6-perf
-  tasks: *benchmark_tests
+  tasks: *benchmark_tests