Updated l10nUtil: nux_strings.grpd was moved.

Moved to onboarding_welcome_strings.grdp.

Chromium change:

commit 395516be219e7d31767e0ba47a5ac5c9f510c1ff
Author: Scott Chen <scottchen@chromium.org>
Date:   Tue Oct 23 00:05:48 2018 +0000

    NUX Onboarding: add some strings

    Replacing placeholder strings, and move all the add-string calls to under
    one function.

    also fixes a path bug for apps/ -> google_apps/ introduced in
    https://chromium-review.googlesource.com/c/chromium/src/+/1285210

    Bug: 874122

lib/l10nUtil.js

@@ -46,8 +46,6 @@ const chromiumProfileSettingsPartPath = path.resolve(path.join(srcDir, 'chrome',
 const braveProfileSettingsPartPath = path.resolve(path.join(srcDir, 'brave', 'app', 'profiles_strings.grdp'))
 const chromiumFileManagerStringsPartPath = path.resolve(path.join(srcDir, 'chrome', 'app', 'file_manager_strings.grdp'))
 const braveFileManagerStringsPartPath = path.resolve(path.join(srcDir, 'brave', 'app', 'file_manager_strings.grdp'))
-const chromiumNuxStringsPartPath = path.resolve(path.join(srcDir, 'chrome', 'app', 'nux_strings.grdp'))
-const braveNuxStringsPartPath = path.resolve(path.join(srcDir, 'brave', 'app', 'nux_strings.grdp'))
 const chromiumVRStringsPartPath = path.resolve(path.join(srcDir, 'chrome', 'app', 'vr_strings.grdp'))
 const braveVRStringsPartPath = path.resolve(path.join(srcDir, 'brave', 'app', 'vr_strings.grdp'))
 const chromiumOnboardingWelcomeStringsPartPath = path.resolve(path.join(srcDir, 'chrome', 'app', 'onboarding_welcome_strings.grdp'))
@@ -82,7 +80,6 @@ const chromiumToAutoGeneratedBraveMapping = {
   [chromiumPrintingStringsPartPath]: bravePrintingStringsPartPath,
   [chromiumProfileSettingsPartPath]: braveProfileSettingsPartPath,
   [chromiumFileManagerStringsPartPath]: braveFileManagerStringsPartPath,
-  [chromiumNuxStringsPartPath]: braveNuxStringsPartPath,
   [chromiumVRStringsPartPath]: braveVRStringsPartPath,
   [chromiumOnboardingWelcomeStringsPartPath]: braveOnboardingWelcomeStringsPartPath,
   [chromiumAppManagementStringsPartPath]: braveAppManagementStringsPartPath