sidebar: Fix loading items of unlocked places

When clicking the unlock button in the sidebar, we automatically select that row. In turn, that activates the base collection to start loading the items that are part of the GkrKeyring, before it's been fully unlocked. As a consequence, we can't load the labels or other relevant information yet.

This commit introduces a (temporary) workaround, which clears the selection (clearing the collection), before selecting the row again, leading to all the items being loaded after the keyring has been unlocked.

Fixes #306 (closed)