Bump the eui group across 1 directory with 2 updates (#1501)

Bumps the eui group with 2 updates in the /src/Elastic.Documentation.Site directory: [@elastic/eui](https://github.com/elastic/eui) and [@elastic/eui-theme-borealis](https://github.com/elastic/eui/tree/HEAD/packages/eui-theme-borealis).


Updates `@elastic/eui` from 104.0.2 to 104.1.0
- [Release notes](https://github.com/elastic/eui/releases)
- [Commits](elastic/eui@v104.0.2...v104.1.0)

Updates `@elastic/eui-theme-borealis` from 3.0.0 to 3.1.0
- [Release notes](https://github.com/elastic/eui/releases)
- [Commits](https://github.com/elastic/eui/commits/v3.1.0/packages/eui-theme-borealis)

---
updated-dependencies:
- dependency-name: "@elastic/eui"
  dependency-version: 104.1.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: eui
- dependency-name: "@elastic/eui-theme-borealis"
  dependency-version: 3.1.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: eui
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/Elastic.Documentation.Site/package-lock.json

@@ -28,8 +28,8 @@
   "private": true,
   "devDependencies": {
     "@elastic/datemath": "5.0.3",
-    "@elastic/eui": "104.0.2",
-    "@elastic/eui-theme-borealis": "3.0.0",
+    "@elastic/eui": "104.1.0",
+    "@elastic/eui-theme-borealis": "3.1.0",
     "@emotion/css": "11.13.5",
     "@emotion/react": "11.14.0",
     "@eslint/js": "9.30.0",