fix: update buffer-layout to fix downstream bundler issues (#18529)

* fix: update buffer-layout to fix downstream bundler issues

* chore: run check on generated type declaration

web3.js/src/bpf-loader.ts

@@ -1,3 +1,5 @@
+import type {Buffer} from 'buffer';
+
 import {PublicKey} from './publickey';
 import {Loader} from './loader';
 import type {Connection} from './connection';