Bug 1739215 - [devtools] Revert `click` to `sendMouseEvent` in browser_webconsole_location_styleeditor_link.js. r=bomsy.

The test is tagged as `fail-if= a11y_checks`, but as patch for Bug 1738124 switched
to Element.click, we don't get the expected failure anymore (since the a11y_check
task does not perform assertion on element.click).
Let's revert to the original behavior so we can still see that the test need
some a11y work.

Differential Revision: https://phabricator.services.mozilla.com/D130610

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

@@ -37,7 +37,10 @@ async function testViewSource(hud, toolbox, text) {
 
   const onStyleEditorSelected = toolbox.once("styleeditor-selected");
 
-  messageNode.querySelector(".frame-link-filename").click();
+  EventUtils.sendMouseEvent(
+    { type: "click" },
+    messageNode.querySelector(".frame-link-filename")
+  );
 
   const panel = await onStyleEditorSelected;
   ok(