Reverts v-if/v-show change from openhab#2029. (openhab#2054)

Regression from openhab#2029.

A few of my UI pages stopped loading properly. Specifically there seemed to be a condition where when the page would draw its widgets before other parts
of the page were loaded (or something similar, some race conditional).
This would result in widgets loading with the wrong state, colors, icons, etc that are dependent on item state.

I tracked it down to this
one very small change, reverting back to a `v-show` from `v-if` for the
main view ready state fixes this.

Signed-off-by: Dan Cunningham <dan@digitaldan.com>
Signed-off-by: Stefan Höhn <mail@stefanhoehn.com>

bundles/org.openhab.ui/web/src/components/app.vue

@@ -141,7 +141,7 @@
       <developer-sidebar />
     </f7-panel>
 
-    <f7-view main v-if="ready" class="safe-areas" url="/" :master-detail-breakpoint="960" :animate="themeOptions.pageTransitionAnimation !== 'disabled'" />
+    <f7-view main v-show="ready" class="safe-areas" url="/" :master-detail-breakpoint="960" :animate="themeOptions.pageTransitionAnimation !== 'disabled'" />
 
   <!-- <f7-login-screen id="my-login-screen" :opened="loginScreenOpened">
     <f7-view name="login" v-if="$device.cordova">