revert change to pages dev mode config loading

packages/wrangler/src/pages/dev.ts

@@ -4,7 +4,7 @@ import { dirname, join, normalize, resolve } from "node:path";
 import { watch } from "chokidar";
 import * as esbuild from "esbuild";
 import { unstable_dev } from "../api";
-import { configFileName, readPagesConfig } from "../config";
+import { configFileName, readConfig } from "../config";
 import { isBuildFailure } from "../deployment-bundle/build-failures";
 import { shouldCheckFetch } from "../deployment-bundle/bundle";
 import { esbuildAliasExternalPlugin } from "../deployment-bundle/esbuild-plugins/alias-external";
@@ -303,10 +303,7 @@ export const Handler = async (args: PagesDevArguments) => {
 
 	// for `dev` we always use the top-level config, which means we need
 	// to read the config file with `env` set to `undefined`
-	const config = readPagesConfig(
-		{ ...args, env: undefined },
-		{ useRedirect: true }
-	);
+	const config = readConfig({ ...args, env: undefined }, { useRedirect: true });
 	const resolvedDirectory = args.directory ?? config.pages_build_output_dir;
 	const [_pages, _dev, ...remaining] = args._;
 	const command = remaining;