Update Firefox 141 release notes for WebDriver conforming changes (mdn#40375)

* Update Firefox 141 release notes for WebDriver conforming changes

* Apply suggestions from code review

Co-authored-by: Henrik Skupin <mail@hskupin.info>

* Update files/en-us/mozilla/firefox/releases/141/index.md

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update files/en-us/mozilla/firefox/releases/141/index.md

Co-authored-by: Henrik Skupin <mail@hskupin.info>

* Update files/en-us/mozilla/firefox/releases/141/index.md

Co-authored-by: Henrik Skupin <mail@hskupin.info>

* Apply suggestions from code review

---------

Co-authored-by: Henrik Skupin <mail@hskupin.info>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: 3 people

files/en-us/mozilla/firefox/releases/141/index.md

@@ -77,13 +77,24 @@ Firefox 141 is the current [Beta version of Firefox](https://www.mozilla.org/en-
 
 <!-- #### Removals -->
 
-<!-- ### WebDriver conformance (WebDriver BiDi, Marionette) -->
+### WebDriver conformance (WebDriver BiDi, Marionette)
 
-<!-- #### General -->
+#### General
 
-<!-- #### WebDriver BiDi -->
+- Removed the temporary `remote.system-access-check.enabled` preference. This preference can no longer be used to disable system access checks when using WebDriver in Firefox's chrome scope during testing ([Firefox bug 1955007](https://bugzil.la/1955007)).
 
-<!-- #### Marionette -->
+#### WebDriver BiDi
+
+- Added support for the "proxy" argument of the `browser.createUserContext` command. This allows clients to setup either a "direct" or "manual" proxy when creating a user context (ie Firefox Container). Support for additional proxy types will be added later on ([Firefox bug 1967653](https://bugzil.la/1967653)).
+- Implemented the new `browsingContext.historyUpdated` event which is emitted when `history.pushState()`, `history.replaceState()` or `document.open()` is called within the context of a web page ([Firefox bug 1906051](https://bugzil.la/1906051)).
+- Improved the error message shown when attempting to permanently install an unpacked, unsigned web extension ([Firefox bug 1958723](https://bugzil.la/1958723)).
+- Updated the `browsingContext.navigate` and `browsingContext.reload` commands to wait for the `browsingContext.navigationCommitted` event when using the "wait" condition "none" ([Firefox bug 1967469](https://bugzil.la/1967469)).
+- Updated the WebDriver BiDi cookie APIs to support "default" value in "sameSite" property to address recent changes in platform API which wouldn't allow anymore to set a cookie with "sameSite=None" and "secure=false" on HTTP pages ([Firefox bug 1971488](https://bugzil.la/1971488)).
+
+#### Marionette
+
+- To avoid unnecessary 200ms delays for each call to `WebDriver:ElementClick` - even when no navigation occurrs - we lowered the click-and-wait timeout for a potential navigation to 50ms for backward compatibility. The [timeout is now also configurable](https://firefox-source-docs.mozilla.org/testing/marionette/Prefs.html#marionette-navigate-after-click-timeout) and [can be completely disabled](https://firefox-source-docs.mozilla.org/testing/marionette/Prefs.html#marionette-navigate-after-click-enabled) by users through a preference ([Firefox bug 1972271](https://bugzil.la/1972271)).
+- Added support in Marionette for interacting with CHIPS cookies (Cookies Having Independent Partitioned State) ([Firefox bug 1972830](https://bugzil.la/1972830)).
 
 ## Changes for add-on developers