Bug 1808115 - Remove the separate EmbedPrompter wrapper, use Prompter instead. r=Gijs,necko-reviewers,geckoview-reviewers,valentin,m_kato

We no longer support the legacy add-ons, so this should not be necessary.

Differential Revision: https://phabricator.services.mozilla.com/D165764

dom/html/HTMLFormElement.cpp

@@ -907,7 +907,7 @@ nsresult HTMLFormElement::DoSecureToInsecureSubmitCheck(nsIURI* aActionURL,
 
   nsresult rv;
   nsCOMPtr<nsIPromptService> promptSvc =
-      do_GetService("@mozilla.org/embedcomp/prompt-service;1", &rv);
+      do_GetService("@mozilla.org/prompter;1", &rv);
   if (NS_FAILED(rv)) {
     return rv;
   }