fix: Fix some minor typing issues.

Author: gonfunko

src/actions/delete.ts

@@ -113,8 +113,8 @@ export class DeleteAction {
         // Run the original precondition code, from the context menu option.
         // If the item would be hidden or disabled, respect it.
         const originalPreconditionResult =
-          this.oldContextMenuItem!.preconditionFn(scope);
-        if (!ws || originalPreconditionResult != 'enabled') {
+          this.oldContextMenuItem!.preconditionFn?.(scope) ?? 'enabled';
+        if (!ws || originalPreconditionResult !== 'enabled') {
           return originalPreconditionResult;
         }