Show loading in FileSelectComponent only when listing files

[jonatanklosko]

As the user types we reuse the directory listing, we only do an actual loading when the directory changes (or the component receives an update to force reload):

livebook/lib/livebook_web/live/file_select_component.ex

Line 706 in 3bc7cca

with {:ok, files} <- FileSystem.File.list(dir) do

Also, ideally we would colocate setting loading: true with the actual listing, rather than setting it "upfront":

livebook/lib/livebook_web/live/file_select_component.ex

Line 549 in 3bc7cca

{:noreply, assign(socket, loading: socket.assigns.file.path != path)}

In order for the UI to update, likely the best way would be to do the listing async in a task.