Workaround: add sleep calls

AFAICT this is now needed because of open-telemetry/opentelemetry-rust#1830

(mentioned in https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-sdk/CHANGELOG.md#v0240)

Replacing install_batch with install_simple also works.

tests/e2e/mod.rs

@@ -27,6 +27,8 @@ async fn get_spans(f: impl FnOnce(), collector_url: &str) -> Option<Vec<Span>> {
         f()
     }
 
+    std::thread::sleep(std::time::Duration::from_secs(5));
+
     let mut client = JaegerTestClient::new(query_api_url);
 
     if !client.contain_service(&service_name).await {
@@ -152,6 +154,8 @@ async fn error_layer_enrich_errored_spans() {
         });
     };
 
+    std::thread::sleep(std::time::Duration::from_secs(5));
+
     let mut client = JaegerTestClient::new(query_api_url);
 
     let spans = if !client.contain_service(&service_name).await {