Skip fish_vi_cursor when not interactive

This prints an escape sequence, so it can break scp or similar when
someone has an unqualified

    fish_vi_key_bindings

in config.fish and happens to run a terminal that can set the cursor.

share/functions/fish_vi_cursor.fish

@@ -13,6 +13,11 @@ function fish_vi_cursor -d 'Set cursor shape for different vi modes'
     # But since tmux in konsole seems rather common and that case so uncommon,
     # we will just fail there (though it seems that tmux or st swallow it anyway).
 
+    # If we're not interactive, there is effectively no bind mode.
+    if not status is-interactive
+        return
+    end
+
     if set -q INSIDE_EMACS
         return
     end