Move command can lead to crash if invoked while category list is filtered

[mtotschnig]

Given:

• Category A with one sub category b
• On Category screen (either opened from transaction form or from Settings), click on search icon an enter A as search term
• Category A now appears without children
• Tap and hold on category A

Expected:

• Move command is not available in contextual action bar because main category with children cannot be moved.

Actual:

• Move command is available and when invoked crashes the app.