(api) set db to null when closing it, hopefully fxing some database handle is closed errors or providing a better stack for others

server/index.ts

@@ -106,6 +106,7 @@ export class LazyDatabase implements Database {
         if (this.db !== null) {
             try {
                 await this.db.close();
+                this.db = null;
             } catch (error) {
                 Sentry.captureException(error);
             }