chore(deps): update stencil core (#30132)

We have shipped various of improvements to the Stencil project and
runtime. You can take a close look at our
[changelog](https://github.com/ionic-team/stencil/blob/main/CHANGELOG.md)
but since `v4.20.0` we mainly shipped improvements on the following
issues:

## Major Improvements:

- Enhanced Shadow DOM and hydration support
  - Improved client-side hydration for SSR
  - Better handling of shadow root styles and component hydration
  - More reliable serialization of Shadow DOM components

## Key Bug Fixes:

- Resolved performance issues due to detached nodes in memory
- Fixed several critical issues with scoped slots and component styling
- Improved handling of SVG class attributes and template tags
- Enhanced runtime decorator functionality
- Better handling of form-associated callbacks

## Technical Updates:

- Updated to TypeScript 5.5
- Added support for customizable Mermaid diagram colors in documentation

I don't see any critical changes that may impact Ionic users and feel
confident we can ship this.

## Dev Build

`8.5.4-dev.11744646756.1244bf71`

---------

Co-authored-by: Brandy Smith <brandyscarney@users.noreply.github.com>

Author: christian-bromann

core/package-lock.json

@@ -31,7 +31,7 @@
     "loader/"
   ],
   "dependencies": {
-    "@stencil/core": "4.20.0",
+    "@stencil/core": "4.29.3",
     "ionicons": "^7.2.2",
     "tslib": "^2.1.0"
   },

core/package.json

@@ -22,10 +22,6 @@ html {
   text-size-adjust: 100%;
 }
 
-html:not(.hydrated) body {
-  display: none;
-}
-
 html.ion-ce body {
   display: block;
 }

core/src/components/split-pane/test/basic/split-pane.e2e.ts-snapshots/split-pane-ios-rtl-Mobile-Safari-linux.png

@@ -243,7 +243,6 @@ export const config: Config = {
     // },
     ...getAngularOutputTargets(),
   ],
-  buildEs5: 'prod',
   testing: {
     moduleNameMapper: {
       "@utils/test": ["<rootDir>/src/utils/test/utils"],

core/src/css/structure.scss

@@ -2,7 +2,7 @@ import { NgZone } from '@angular/core';
 import type { Config, IonicWindow } from '@ionic/angular/common';
 import { raf } from '@ionic/angular/common';
 import { setupConfig } from '@ionic/core';
-import { applyPolyfills, defineCustomElements } from '@ionic/core/loader';
+import { defineCustomElements } from '@ionic/core/loader';
 
 // TODO(FW-2827): types
 
@@ -18,19 +18,17 @@ export const appInitialize = (config: Config, doc: Document, zone: NgZone) => {
       const aelFn =
         '__zone_symbol__addEventListener' in (doc.body as any) ? '__zone_symbol__addEventListener' : 'addEventListener';
 
-      return applyPolyfills().then(() => {
-        return defineCustomElements(win, {
-          exclude: ['ion-tabs'],
-          syncQueue: true,
-          raf,
-          jmp: (h: any) => zone.runOutsideAngular(h),
-          ael(elm, eventName, cb, opts) {
-            (elm as any)[aelFn](eventName, cb, opts);
-          },
-          rel(elm, eventName, cb, opts) {
-            elm.removeEventListener(eventName, cb, opts);
-          },
-        });
+      return defineCustomElements(win, {
+        exclude: ['ion-tabs'],
+        syncQueue: true,
+        raf,
+        jmp: (h: any) => zone.runOutsideAngular(h),
+        ael(elm, eventName, cb, opts) {
+          (elm as any)[aelFn](eventName, cb, opts);
+        },
+        rel(elm, eventName, cb, opts) {
+          elm.removeEventListener(eventName, cb, opts);
+        },
       });
     }
   };

core/stencil.config.ts

@@ -3,7 +3,7 @@
   "compilerOptions": {
     "outDir": "../out-tsc/e2e",
     "module": "commonjs",
-    "target": "es5",
+    "target": "ES2022",
     "types": ["cypress", "node"]
   },
   "include": [