feat: remove empty protos ServiceMonitoringProto and DrilldownsProto (#421)

Author: Neenu1995

owlbot.py

@@ -14,10 +14,13 @@
 
 import synthtool as s
 from synthtool.languages import java
+import os
 
 
 for library in s.get_staging_dirs():
     # put any special-case replacements here
+    os.remove("owl-bot-staging/v1/proto-google-cloud-monitoring-dashboard-v1/src/main/java/com/google/monitoring/dashboard/v1/DrilldownsProto.java")
+    os.remove("owl-bot-staging/v1/proto-google-cloud-monitoring-dashboard-v1/src/main/java/com/google/monitoring/dashboard/v1/ServiceMonitoringProto.java")
     s.move(library)
 
 s.remove_staging_dirs()

proto-google-cloud-monitoring-dashboard-v1/clirr-ignored-differences.xml

@@ -16,4 +16,13 @@
     <className>com/google/monitoring/dashboard/v1/*OrBuilder</className>
     <method>boolean has*(*)</method>
   </difference>
+
+  <difference>
+    <differenceType>8001</differenceType>
+    <className>com/google/monitoring/dashboard/v1/DrilldownsProto</className>
+  </difference>
+  <difference>
+    <differenceType>8001</differenceType>
+    <className>com/google/monitoring/dashboard/v1/ServiceMonitoringProto</className>
+  </difference>
 </differences>