Update SMS shortcodes

Add shortcode 88778 to safelist for Mexico
Add shortcode 176 to safelist for New Zealand
Add shortcode 1355 to safelist for Arab Emirates
Add shortcode 44136 to safelist for South Africa

Bug: 143704258
Test: Tests performed by Salvatore Baglieri.
Change-Id: Ifc9024e6bbb9592ccaa35fc16ce45af3a016de95