Revert "Don't automatically start Florence: the Florence Indicator GNOME Shell...

Revert "Don't automatically start Florence: the Florence Indicator GNOME Shell extension will start it the first time one tries to display it."

This reverts commit 98838908.

The GNOME Shell extension we use has logic to avoid double-starting Florence,
using a hard-coded delay. I've seen it fail (possibly due to our time sync'
system, or just because that hard-coded delay may cause robustness issues
depending on the hardware). When it fails, then the toggle logic is completely
broken in terms of UX, since hiding one instance of the virtual keyboard
shows the next one, etc.