Layout HTML frame shows error: WebKit not available!

### What is the bug or the crash? With QGIS 4.0.0, adding an HTML frame to a layout results in a red box with the the following message: "WebKit not available! This item cannot be rendered because this QGIS install was built without WebKit support." ### Steps to reproduce the issue 1. Download and Install QGIS 4.0.0 from latest release binary on Windows 11 2. Open QGIS and create a new layout 3. Add an HTML frame to the layout 4. Note the contents of the HTML frame do not change whether using a URL or providing custom HTML source code ### Versions

QGIS version	4.0.0-Norrköping
QGIS code revision	1ddcee3d0e4
Libraries
Qt version	6.8.1
Python version	3.12.13
GDAL version	3.12.2 — Chicoutimi
PROJ version	9.8.0
EPSG Registry database version	v12.049 (2026-02-14)
GEOS version	3.14.1-CAPI-1.20.5
SFCGAL version	No support
GeographicLib version	2.7.0
SQLite version	3.50.4
PDAL version	2.10.0
PostgreSQL client version	17.3
SpatiaLite version	5.1.0
QWT version	6.3.0
QScintilla2 version	2.14.1
OS version	Windows 11 Version 24H2
Active Python plugins
MetaSearch	0.3.6
db_manager	0.1.20
grassprovider	2.12.99
processing	2.12.99

### Supported QGIS version - [x] I'm running a supported QGIS version according to [the roadmap](https://www.qgis.org/en/site/getinvolved/development/roadmap.html#release-schedule). ### New profile - [x] I tried with a new [QGIS profile](https://docs.qgis.org/latest/en/docs/user_manual/introduction/qgis_configuration.html#working-with-user-profiles) ### Additional context _No response_