workspacesView: sync gesture enabled state after setting it up completely

workspacesView: sync gesture enabled state after setting it up completely

At the point it is disabled, it has got signal handlers connected but
this._workspacesView is uninitialized. This triggers:

(gnome-shell:3993): Gjs-WARNING **: 18:49:53.281: JS ERROR: Exception in callback for signal: cancel: TypeError: this._workspacesViews is undefined
_endTouchGesture@resource:///org/gnome/shell/ui/workspacesView.js:527:25
_emit@resource:///org/gnome/gjs/modules/signals.js:142:27
set enabled@resource:///org/gnome/shell/ui/windowManager.js:478:13
WorkspacesDisplay<@resource:///org/gnome/shell/ui/workspacesView.js:482:9
ViewSelector<@resource:///org/gnome/shell/ui/viewSelector.js:167:35
ControlsManager<@resource:///org/gnome/shell/ui/overviewControls.js:405:29
init@resource:///org/gnome/shell/ui/overview.js:234:26
_initializeUI@resource:///org/gnome/shell/ui/main.js:184:5
start@resource:///org/gnome/shell/ui/main.js:124:5
@<main>:1:31

On startup. Shuffling these two lines prevent this from happening.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/506