chore: remove some unused code (#16455)

Author: Rich-Harris

packages/svelte/src/internal/client/reactivity/props.js

@@ -1,13 +1,11 @@
-/** @import { ComponentContext } from '#client' */
-/** @import { Derived, Effect, Source } from './types.js' */
+/** @import { Effect, Source } from './types.js' */
 import { DEV } from 'esm-env';
 import {
 	PROPS_IS_BINDABLE,
 	PROPS_IS_IMMUTABLE,
 	PROPS_IS_LAZY_INITIAL,
 	PROPS_IS_RUNES,
-	PROPS_IS_UPDATED,
-	UNINITIALIZED
+	PROPS_IS_UPDATED
 } from '../../../constants.js';
 import { get_descriptor, is_function } from '../../shared/utils.js';
 import { set, source, update } from './sources.js';