dev-cmd/tests: Deal with TODO for a BuildPulse bug that's fixed

- This does what the comment told us to do, use the bang variant of
  `system_command` to not swallow the errors.

Library/Homebrew/dev-cmd/tests.rb

@@ -60,8 +60,7 @@ module Homebrew
 
     ohai "Sending test results to BuildPulse"
 
-    # TODO: make this use `system_command!` when https://github.com/buildpulse/buildpulse-action/issues/4 is fixed
-    system_command Formula["buildpulse-test-reporter"].opt_bin/"buildpulse-test-reporter",
+    system_command! Formula["buildpulse-test-reporter"].opt_bin/"buildpulse-test-reporter",
                     args: [
                       "submit", "#{HOMEBREW_LIBRARY_PATH}/test/junit",
                       "--account-id", ENV.fetch("HOMEBREW_BUILDPULSE_ACCOUNT_ID"),