Fix TAB fallthrough if yas-minor-mode is disabled

yas-expand will error out if yas-minor-mode is disabled, preventing TAB
from falling through to the next action.

modules/config/default/+evil-bindings.el

@@ -27,6 +27,7 @@
       ;; Smart tab
       :i [tab] (general-predicate-dispatch nil ; fall back to nearest keymap
                  (and (featurep! :feature snippets)
+                      (bound-and-true-p yas-minor-mode)
                       (yas-maybe-expand-abbrev-key-filter 'yas-expand))
                  'yas-expand
                  (and (featurep! :completion company +tng)