fix(astro): refine assets prefix typing (#11020)

Author: xsynaptic

.changeset/seven-crabs-burn.md

@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Add type declarations for `import.meta.env.ASSETS_PREFIX` when defined as an object for handling different file types.

packages/astro/client.d.ts

@@ -12,7 +12,7 @@ interface ImportMetaEnv {
 	/**
 	 * The prefix for Astro-generated asset links if the build.assetsPrefix config option is set. This can be used to create asset links not handled by Astro.
 	 */
-	readonly ASSETS_PREFIX: string;
+	readonly ASSETS_PREFIX: string | Record<string, string>;
 	/**
 	 * This is set to the site option specified in your project’s Astro config file.
 	 */