Bug 1569123 - Re-enable strict MIME type checking for Worker/SharedWorker everywhere. r=ckerschb

Differential Revision: https://phabricator.services.mozilla.com/D63056

--HG--
extra : moz-landing-system : lando

devtools/client/webconsole/test/browser/browser_webconsole_non_javascript_mime_worker_error.js

@@ -19,10 +19,6 @@ const MIME_ERROR_MSG1 = `Loading Worker from “${JS_URI}” was blocked because
 const MIME_ERROR_MSG2 = `Loading script from “${JS_URI}” with importScripts() was blocked because of a disallowed MIME type (“text/plain”).`;
 
 add_task(async function() {
-  await SpecialPowers.pushPrefEnv({
-    set: [["security.block_Worker_with_wrong_mime", true]],
-  });
-
   const hud = await openNewTabAndConsole(TEST_URI);
   await waitFor(
     () => findMessage(hud, MIME_ERROR_MSG1, ".message.error"),

modules/libpref/init/StaticPrefList.yaml

@@ -7820,7 +7820,7 @@
 # Block Worker/SharedWorker scripts with wrong MIME type.
 - name: security.block_Worker_with_wrong_mime
   type: bool
-  value: @IS_EARLY_BETA_OR_EARLIER@
+  value: true
   mirror: always
 
 #---------------------------------------------------------------------------