[Svelte] Fix version detection because svelte/compiler isn't available browser side

Author: ChqThomas

src/Svelte/assets/dist/render_controller.js

@@ -1,5 +1,4 @@
 import { Controller } from '@hotwired/stimulus';
-import { VERSION } from 'svelte/compiler';
 
 class default_1 extends Controller {
     async connect() {
@@ -39,8 +38,8 @@ class default_1 extends Controller {
         this.dispatch(name, { detail, prefix: 'svelte' });
     }
     async mountSvelteComponent(Component, options) {
-        if (VERSION?.startsWith('5')) {
-            const { mount } = await import('svelte');
+        const { mount } = await import('svelte');
+        if (mount) {
             return mount(Component, options);
         }
         return new Component(options);

src/Svelte/assets/src/render_controller.ts

@@ -1,6 +1,5 @@
 import { Controller } from '@hotwired/stimulus';
 import type { SvelteComponent, ComponentConstructorOptions, ComponentType } from 'svelte';
-import { VERSION as SVELTE_VERSION } from 'svelte/compiler';
 
 export default class extends Controller<Element & { root?: SvelteComponent }> {
     private app: SvelteComponent;
@@ -70,9 +69,10 @@ export default class extends Controller<Element & { root?: SvelteComponent }> {
         Component: ComponentType,
         options: ComponentConstructorOptions
     ): Promise<SvelteComponent> {
-        if (SVELTE_VERSION?.startsWith('5')) {
-            // @ts-ignore
-            const { mount } = await import('svelte');
+        // @ts-ignore
+        const { mount } = await import('svelte');
+        if (mount) {
+            // `mount` is only available in Svelte >= 5
             return mount(Component, options);
         }