Tests: run the multi-req tests first (#643)

Author: gaborcsardi

DESCRIPTION

@@ -50,7 +50,7 @@ VignetteBuilder:
 Config/Needs/website: tidyverse/tidytemplate
 Config/testthat/edition: 3
 Config/testthat/parallel: true
-Config/testthat/start-first: resp-stream, req-perform
+Config/testthat/start-first: multi-req, resp-stream, req-perform
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2