Fix request #7423: Add alternate text to button "Enable notifications" on artifacts

Change-Id: Idc5bf9718b642bc5623a7bfefee29b8dcd8e2f08
Merge commit 'refs/changes/81/2981/4' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  Fix request #7423: Add alternate text to button "Enable notifications" on artifacts

Change-Id: I0de35d47b866b7a995801da5ebb3b6b2c19eb4dd
This is Tuleap 7.4.99.31

Change-Id: I72233d47d7af6f15ca0afc86c87bcbcbec683f5c