Removed link's underline from settings UI

fix brave/brave-browser#26091

Below upstream's change enabled underline.
https://chromium-review.googlesource.com/c/chromium/src/+/3855278
WebUI: Decorate links with underline

This is part 1 of decorating all links and all buttons that look like
links with the underline to help users better differentiate between
normal text and actionable links. This CL updates links on Settings,
Extensions, Management, Downloads, and Welcome, as well as updating
a couple of global WebUI styles.

patches/chrome-browser-resources-settings-settings_shared.css.patch

@@ -0,0 +1,14 @@
+diff --git a/chrome/browser/resources/settings/settings_shared.css b/chrome/browser/resources/settings/settings_shared.css
+index b28284ade36d1ad8a695e6532b74edc406dcc067..e82a56cecd818b5636f0b59373353a2fda19b3f3 100644
+--- a/chrome/browser/resources/settings/settings_shared.css
++++ b/chrome/browser/resources/settings/settings_shared.css
+@@ -9,7 +9,8 @@
+  * #import=//resources/cr_elements/search_highlight_style.css.js
+  * #import=./settings_vars.css.js
+ <if expr='not chromeos_ash'>
+- * #include=cr-shared-style search-highlight-style
++ * #import=//resources/page_specific/settings/br_settings_shared.css.js
++ * #include=cr-shared-style search-highlight-style br-settings-shared
+ </if>
+ <if expr='chromeos_ash'>
+  * #import=//resources/cr_elements/chromeos/cros_color_overrides.m.js

ui/webui/resources/page_specific/settings/br_settings_shared.css

@@ -0,0 +1,12 @@
+/* Copyright (c) 2022 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * you can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* #css_wrapper_metadata_start
+ * #type=style
+ * #css_wrapper_metadata_end */
+
+a[href] {
+  text-decoration: none !important;
+}

ui/webui/resources/sources.gni

@@ -65,6 +65,7 @@ if (include_polymer) {
     "br_elements/br_shared_vars.css",
     "overrides/cr_button_override.css",
     "overrides/cr_toggle_override.css",
+    "page_specific/settings/br_settings_shared.css",
   ]
 
   # Files that are generated by css_to_wrapper().