fix(quick-actions): drop the folder-scoped session rows

The status-bar launcher carried a "Sessions" group holding "Manage
conversations" and "Import local sessions". Both act on ONE folder, and the
launcher has no folder of its own — it reached for whichever happened to be
active, and greyed the manage row out entirely when none was. That is not what a
folder-scoped action means, and both already live where a folder is: manage in
the folder row's context menu, import there and on the Folders section header.

The group goes, and with it the conversation-manage dialog the launcher was
mounting, the active-folder subscription that fed only these two rows, and the
`groups.sessions` heading across all ten locales. What is left is workspace,
navigation and the pet — every row of which acts on the app rather than on a
folder, so none of them needs a folder to be active to mean anything.