[Feature Request] Remove Newtonsoft.Json from MSAL and use System.Text.Json

[bgavrilMS]

MSAL client type

Public, Confidential, Managed identity

Problem statement

With MSAL 4.66.0 and below, only the .NET version of MSAL uses System.Text.Json. The rest of the tfms use an internal copy of Newtonsoft.Json

This poses several problems:

• Need to keep Newtonsoft.Json up to date, particularly when it has CVEs
• If CVE occurs, MSAL is not notified because Newtonsoft is referenced by code not by project.
• MSAL needs to dual-stack Newtonsoft and System.Text.Json, which complicates JSON operations and MSAL code
• System.Text.Json + source generation is faster

Proposed solution

Reference System.Text.Json version 6.0.11 (this is what other Identity SDKs use).

Alternatives

No response