[CHORE] Name the path the test timeout is there for, and say what success means now

The bound guards the synchronous wiring cases, which wait on a completion. The
asynchronous fake calls back from inside SendRequest() and Export() returns without
waiting, so it is not what a stranded completion would hang.

The changelog said an acknowledgement carries a 2xx status. It carries one that says the
operation applied, which is a narrower thing, and the batch status it sits under is
narrower still.

Signed-off-by: thc1006 <84045975+thc1006@users.noreply.github.com>

Author: thc1006

CHANGELOG.md

@@ -152,7 +152,10 @@ Increment the:
 
 * [BUG] Decide Elasticsearch bulk export success from the HTTP status, the
   errors flag, and one acknowledgement per record that names its target index
-  and carries a 2xx status
+  and says the operation applied
+  [#4297](https://github.com/open-telemetry/opentelemetry-cpp/pull/4297)
+* [BUG] Stop reading an Elasticsearch bulk response that only says the request
+  was accepted as a batch that was written
   [#4297](https://github.com/open-telemetry/opentelemetry-cpp/pull/4297)
 
 * [BUG] Make SocketAddr string parsing safe and reject malformed addresses

exporters/elasticsearch/CMakeLists.txt

@@ -62,8 +62,9 @@ if(BUILD_TESTING)
     TEST_PREFIX exporter.
     TEST_LIST es_log_record_exporter_test)
 
-  # The asynchronous cases wait on a response that a regression can stop
-  # delivering, and a case that hangs stops the job rather than reporting. A
-  # bound turns that back into a red test.
+  # The synchronous wiring cases wait on a completion, and a regression that
+  # stops delivering one hangs the job rather than reporting. A bound turns that
+  # back into a red test. Not the asynchronous ones: their fake calls back from
+  # inside SendRequest() and Export() returns without waiting.
   set_tests_properties(${es_log_record_exporter_test} PROPERTIES TIMEOUT 120)
 endif() # BUILD_TESTING