chore: fix Anki open check

make/install.mk

@@ -3,7 +3,7 @@ ANKI_COL_WAL := $(ANKI_COL_DIR)/collection.anki2-wal
 
 .PHONY: install
 install: $(APKGS)
-	$(if $(wildcard $(ANKI_COL_DIR)), $(error Cannot install while Anki is open))
+	$(if $(wildcard $(ANKI_COL_WAL)), $(error Cannot install while Anki is open))
 # make sure data gets overwritten by deleting old data first
 	-rm $(ANKI_COL_DIR)/collection.media/_hd*.js
 # not running with pipenv because we explicitly want the system anki