Bump html-webpack-plugin from 4.5.2 to 5.6.0 in /services/idp

Bumps [html-webpack-plugin](https://github.com/jantimon/html-webpack-plugin) from 4.5.2 to 5.6.0.
- [Release notes](https://github.com/jantimon/html-webpack-plugin/releases)
- [Changelog](https://github.com/jantimon/html-webpack-plugin/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jantimon/html-webpack-plugin/compare/v4.5.2...v5.6.0)

---
updated-dependencies:
- dependency-name: html-webpack-plugin
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

services/idp/package.json

@@ -131,7 +131,7 @@
     "eslint-plugin-testing-library": "^3.10.2",
     "eslint-webpack-plugin": "^2.7.0",
     "file-loader": "6.2.0",
-    "html-webpack-plugin": "4.5.2",
+    "html-webpack-plugin": "5.6.0",
     "i18next-conv": "^14.1.0",
     "i18next-parser": "^8.13.0",
     "jest": "29.7.0",