Bump the minimum supported Chrome version to 128 (#2786)

A bug in the chrome.declarativeNetRequest API[1] meant that extensions could
block requests initiated by other extensions. This cross-extension request
blocking wasn't supposed to be possible[2], and led to lots of issues for users
with multiple browser extensions installed (for example, see this Privacy Badger
bug report[3]).

These cross-extension requests weren't associated with a tabId, and so could not
be differentiated from other such requests - including ServiceWorker initiated
requests. As a workaround, to avoid breaking the other extensions our users
might have installed, we stopped blocking any requests with no associated tabId.

Since then, we have fixed the bug in Chrome[4], and that fix was release with
Chrome 128. So let's increase the minimum supported Chrome version to 128, so
that we can re-enable ServiceWorker initiated request blocking in the future.

1 - https://crbug.com/40896400
2 - w3c/webextensions#369
3 - EFForg/privacybadger#2968
4 - https://chromiumdash.appspot.com/commit/486d638e6977dad73bd207dc914df9319afac152

browsers/chrome/manifest.json

@@ -3,7 +3,7 @@
     "description": "__MSG_appDesc__",
     "default_locale": "en",
     "version": "2024.10.16",
-    "minimum_chrome_version": "121.0",
+    "minimum_chrome_version": "128.0",
     "icons": {
         "16": "img/icon_16.png",
         "48": "img/icon_48.png",