Prevent Svelte HMR warning during the build (withastro#4057)

Author: matthewp

.changeset/lucky-phones-mix.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/svelte': patch
+---
+
+Remove Svelte HMR warning during the build

packages/integrations/svelte/src/index.ts

@@ -38,6 +38,11 @@ function getViteConfiguration({
 		],
 	};
 
+	// Disable hot mode during the build
+	if(!isDev) {
+		defaultOptions.hot = false;
+	}
+
 	let resolvedOptions: Partial<Options>;
 
 	if (!options) {