Bug 1886268 - Add exceptions from a11y_checks for two clicks on non-interactive elements in Settings UI. r=settings-reviewers,Gijs

The `browser/browser/components/preferences/tests/browser_subdialogs.js` sends two clicks on the following non-interactive element to check the closing of the opened dialog using an alternative way of the popup dismissal is working as expected:
1. [label with "dialogTitle" class](https://searchfox.org/mozilla-central/rev/09b59a7de6848639f27297888889a06e97561074/browser/components/preferences/tests/browser_subdialogs.js#407-414) to confirm nothing happens
1. [overlay background with "dialogTemplate" ID](https://searchfox.org/mozilla-central/rev/09b59a7de6848639f27297888889a06e97561074/browser/components/preferences/tests/browser_subdialogs.js#416-435) to confirm clicking outside of the dialog does, in fact, closes it.

For users of keyboards and assistive technology another way like pressing `Esc` key is available to dismiss the dialog, thus we need to add exceptions from the a11y_checks for this tests via `setEnv` and remove the `fail-if` notation from its test manifest.

Differential Revision: https://phabricator.services.mozilla.com/D205120

Author: anna-yeddi

browser/components/preferences/tests/browser.toml

@@ -276,7 +276,6 @@ support-files = [
   "subdialog.xhtml",
   "subdialog2.xhtml",
 ]
-fail-if = ["a11y_checks"] # Bug 1854636 clicked label.dialogTitle, vbox#dialogTemplate.dialogOverlay may not be focusable
 
 ["browser_sync_chooseWhatToSync.js"]
 

browser/components/preferences/tests/browser_subdialogs.js

@@ -407,17 +407,29 @@ add_task(async function background_click_should_close_dialog() {
   // Clicking on an inactive part of dialog itself should not close the dialog.
   // Click the dialog title bar here to make sure nothing happens.
   info("clicking the dialog title bar");
+  // We intentionally turn off this a11y check, because the following click
+  // is purposefully targeting a non-interactive element to confirm the opened
+  // dialog won't be dismissed. It is not meant to be interactive and is not
+  // expected to be accessible, therefore this rule check shall be ignored by
+  // a11y_checks suite.
+  AccessibilityUtils.setEnv({ mustHaveAccessibleRule: false });
   BrowserTestUtils.synthesizeMouseAtCenter(
     ".dialogTitle",
     {},
     tab.linkedBrowser
   );
+  AccessibilityUtils.resetEnv();
 
   // Close the dialog by clicking on the overlay background. Simulate a click
   // at point (2,2) instead of (0,0) so we are sure we're clicking on the
   // overlay background instead of some boundary condition that a real user
   // would never click.
   info("clicking the overlay background");
+  // We intentionally turn off this a11y check, because the following click
+  // is purposefully targeting a non-interactive element to dismiss the opened
+  // dialog with a mouse which can be done by assistive technology and keyboard
+  // by pressing `Esc` key, this rule check shall be ignored by a11y_checks.
+  AccessibilityUtils.setEnv({ mustHaveAccessibleRule: false });
   await close_subdialog_and_test_generic_end_state(
     tab.linkedBrowser,
     function () {
@@ -432,6 +444,7 @@ add_task(async function background_click_should_close_dialog() {
     0,
     { runClosingFnOutsideOfContentTask: true }
   );
+  AccessibilityUtils.resetEnv();
 });
 
 add_task(async function escape_should_close_dialog() {