Fix images not loading in theme app extensions

Our wrapper around fs's `readFile` sets a default of `{encoding:
'utf8'}` to the options. This will cause any binary files (like images
or fonts) to not be read properly.

There isn't a way to disable the encoding based on how the function is
currently typed so I'm switching to fs's version of `readFile` which
will handle all file types correctly automatically.

Author: graygilmore

.changeset/frank-oranges-juggle.md

@@ -0,0 +1,5 @@
+---
+'@shopify/cli-kit': patch
+---
+
+Fix zip and brotliCompress functions to handle binary files

packages/cli-kit/src/public/node/archiver.ts

@@ -1,8 +1,9 @@
 import {relativePath, joinPath, dirname} from './path.js'
-import {glob, removeFile, readFile} from './fs.js'
+import {glob, removeFile} from './fs.js'
 import {outputDebug, outputContent, outputToken} from '../../public/node/output.js'
 import archiver from 'archiver'
 import {createWriteStream, readFileSync, writeFileSync} from 'fs'
+import {readFile} from 'fs/promises'
 import {tmpdir} from 'os'
 import {randomUUID} from 'crypto'