Have a good default focus on 'new chat' and 'add contact'

While 05e527fe helped for `Add contact' it broke 'Start chat' dialog since it always put the focus into the 'Add contact' child of the stack. This moves the focus only to 'Add contact' if that part of the stack is shown. The search bar then grabs the focus back itself.

This is the first half of #329 (closed)

added 1 commit

• e9954d47 - new-chat: Grab input when switching to 'Add contact'

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changed the description

added 9 commits

• e9954d47...7334be5d - 7 commits from branch Librem5:master
• 4fc55b64 - new-chat: Set focus to search field
• 9c2b49e0 - new-chat: Grab input when switching to 'Add contact'

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lgtm. Thanks for the fix

merged