ESQL: Fix test name for duplicate tests (elastic#106297)

When we run the csv-spec tests for ESQL against a real http endpoint we
actually run them twice - once async and once sync. But the names of the
tests didn't reflect that - they just looked like they were accidentally
duplicated. This updates the format. So this:
```
test {string.Trim}
test {string.Trim #2}
```

becomes:
```
test {string.Trim ASYNC}
test {string.Trim SYNC}
```

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/EsqlSpecTestCase.java

@@ -67,7 +67,7 @@ public enum Mode {
         ASYNC
     }
 
-    @ParametersFactory(argumentFormatting = "%2$s.%3$s")
+    @ParametersFactory(argumentFormatting = "%2$s.%3$s %6$s")
     public static List<Object[]> readScriptSpec() throws Exception {
         List<URL> urls = classpathResources("/*.csv-spec");
         assertTrue("Not enough specs found " + urls, urls.size() > 0);