Pontoon: Update Italian (it) localization of Nimbus Experiments

Co-authored-by: Translation Memory <[email protected]>

it/subset/npo_sign_up_sign_in_button_text_change_2024.ftl

@@ -0,0 +1,9 @@
+# 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/.
+
+
+## Branch: treatment-a
+
+# The button text of a button that when clicked allows a user to either sign in to an existing firefox account, or to sign up for one if they don't already have one.
+nuo-sign-up-or-sign-in-button = Registrati o accedi