fix: make `ComponentType` generic optional

fixes #9975

.changeset/red-doors-own.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: make `ComponentType` generic optional

packages/svelte/src/main/public.d.ts

@@ -177,7 +177,7 @@ export type ComponentProps<Comp extends SvelteComponent> = Comp extends SvelteCo
  * <svelte:component this={componentOfCertainSubType} needsThisProp="hello" />
  * ```
  */
-export type ComponentType<Comp extends SvelteComponent> = (new (
+export type ComponentType<Comp extends SvelteComponent = SvelteComponent> = (new (
 	options: ComponentConstructorOptions<
 		Comp extends SvelteComponent<infer Props> ? Props : Record<string, any>
 	>

packages/svelte/types/index.d.ts

@@ -178,7 +178,7 @@ declare module 'svelte' {
 	 * <svelte:component this={componentOfCertainSubType} needsThisProp="hello" />
 	 * ```
 	 */
-	export type ComponentType<Comp extends SvelteComponent> = (new (
+	export type ComponentType<Comp extends SvelteComponent = SvelteComponent> = (new (
 		options: ComponentConstructorOptions<
 			Comp extends SvelteComponent<infer Props> ? Props : Record<string, any>
 		>