chore(deps): bump @microsoft/typespec-msgraph in /additions

Bumps [@microsoft/typespec-msgraph](https://github.com/microsoftgraph/typespec-msgraph) from 1.0.0-Preview.7 to 1.0.0-Preview.8.
- [Commits](https://github.com/microsoftgraph/typespec-msgraph/commits)

---
updated-dependencies:
- dependency-name: "@microsoft/typespec-msgraph"
  dependency-version: 1.0.0-Preview.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

additions/package-lock.json

@@ -4,7 +4,7 @@
   "type": "module",
   "private": true,
   "dependencies": {
-    "@microsoft/typespec-msgraph": "^1.0.0-Preview.7",
+    "@microsoft/typespec-msgraph": "^1.0.0-Preview.8",
     "@typespec/compiler": "latest",
     "@typespec/http": "latest",
     "@typespec/openapi": "latest",