test[es]: Force batch size 1 in test (jaegertracing#4865)

## Which problem is this PR solving?
- Resolves jaegertracing#4743

The test is still failing:
https://github.com/jaegertracing/jaeger/actions/runs/6577136964/job/17868105418#step:7:461

From the logs we can see that the new client is started to be used (HEAD
requests with new password), but then a bulk request with password1
comes in and breaks the test.

## Description of the changes
- Set BulkSize to -1, which according to the driver docs disables bulk
processing.

## How was this change tested?
- Local test is successful, but the issue is difficult to reproduce

---------

Signed-off-by: Yuri Shkuro <github@ysh.us>

plugin/storage/es/factory_test.go

@@ -303,12 +303,14 @@ func testPasswordFromFile(t *testing.T, f *Factory, getClient func() es.Client,
 		Servers:          []string{server.URL},
 		LogLevel:         "debug",
 		PasswordFilePath: pwdFile,
+		BulkSize:         -1, // disable bulk; we want immediate flush
 	}
 	f.archiveConfig = &escfg.Configuration{
 		Enabled:          true,
 		Servers:          []string{server.URL},
 		LogLevel:         "debug",
 		PasswordFilePath: pwdFile,
+		BulkSize:         -1, // disable bulk; we want immediate flush
 	}
 	require.NoError(t, f.Initialize(metrics.NullFactory, zaptest.NewLogger(t)))
 	defer f.Close()