Always return available for SyncClassView command

[JoeRobich]

Fixes https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1070152

Calling View.SynchronizeClassView using keyboard shortcut is not working anymore.

View.SynchronizeClassView is registered to a keyboard shortcut (Alt+M). The shortcut is not shared with other commands and was working fine with version 16.3.10.

Under 16.4.0, doing the keyboard shortcut is not working anymore. I have no idea if the shortcut system itself is broken or if the call to “View.SynchronizeClassView” is broken.

I’m using the very same solution in my tests between version 16.3.10 (working) and 16.4.0 (not working).

I tried changing the shortcut but the result is still the same, not working.
I only ear a beep sound (ding.wav) and nothing happens.

The change in 8259140 removes code that intercepted availability requests in order to always reply available. The SyncClassView CommandHandler should have been updated to reply accordingly. This fix implements that behavior.

[jasonmalinowski]

We may want to target this against non-vs-deps so the change does flow into master instead of master-vs-deps.