fix: [stable-8.0] Remove the unmarshalable request body field from graph log messages

[2403905]

Backport of #12915 to stable-8.0.

Summary

• We've removed the body field from the log messages of the graph service's HTTP handlers. The field was set from http.Request.Body, an io.ReadCloser, which can never be serialized into a useful log value.

[kw-security]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.