sockaddr resolver: skip empty addresses in target URI (#28695)

* Adding constraints to the number of parsed targets in a specified URI to prevent OOMs

* removing hard limit on number of addresses in target uri

src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc

@@ -91,6 +91,10 @@ bool ParseUri(const URI& uri,
   // Construct addresses.
   bool errors_found = false;
   for (absl::string_view ith_path : absl::StrSplit(uri.path(), ',')) {
+    if (ith_path.empty()) {
+      // Skip targets which are empty.
+      continue;
+    }
     auto ith_uri = URI::Create(uri.scheme(), "", std::string(ith_path), {}, "");
     grpc_resolved_address addr;
     if (!ith_uri.ok() || !parse(*ith_uri, &addr)) {