Bug 1494282 - Remove references to onboarding from l10n.toml r=Pike

Differential Revision: https://phabricator.services.mozilla.com/D14053

--HG--
extra : moz-landing-system : lando

browser/locales/l10n.toml

@@ -128,10 +128,6 @@ locales = [
     reference = "browser/extensions/formautofill/locales/en-US/**"
     l10n = "{l}browser/extensions/formautofill/**"
 
-[[paths]]
-    reference = "browser/extensions/onboarding/locales/en-US/**"
-    l10n = "{l}browser/extensions/onboarding/**"
-
 [[paths]]
     reference = "browser/extensions/webcompat-reporter/locales/en-US/**"
     l10n = "{l}browser/extensions/webcompat-reporter/**"