Disable the topIcons GNOME Shell extension in one Tails release

As suggested on #8310-note_21, in order to learn how much our users rely on this extension and — transitively — on OpenPGP Applet, we should disable this extension for one Tails release. People could still enable it again with 1 command line:

gnome-shell-extension-tool --enable-extension=TopIcons@phocean.net

Besides, the OpenPGP Applet will still be available in the bottom-left semi-hidden sysAtray.

:sajolida: is watching this

Feature Branch: bugfix/16608-disable-topicons

Parent Task: #8309

Related issues

• Related to #16399 (closed)
• Related to #16709 (closed)
• Blocks #16209
• Blocks #8310

Original created by @intrigeri on 16608 (Redmine)