[Bug] WithClientClaims doesn't work with nested JSON objects

[bgavrilMS]

Library version used

4.79.0

.NET version

WithClientClaims works with simple custom assertion claims, but not complex ones. We need to ensure that CX can inject a claim like the custom_claims below

{
  "alg": "RS256",
  "x5t": "wHXXbOc3MX66g1j_e_YpH_YdMuo",
}.{
  "aud": "https://login.windows-ppe.net/f435658b-a8c3-4460-adf2-84617caef396/oauth2/token",
  "iss": "6d8ae3e0-2647-41ce-a5f4-0758f10c74a9",
  "sub": "6d8ae3e0-2647-41ce-a5f4-0758f10c74a9",
  "jti": "2DC43547-236D-4199-B7B9-85CF1B4F3D84",
  "exp": 1763585509,
  "nbf": 1763584909,
  "custom_claims": {
    "xms_foo": [
      "abc",
      "def"
    ],
    "xms_az_foo": "bar"
  }
}.[Signature]

Scenario

ConfidentialClient - service to service (AcquireTokenForClient)

Is this a new or an existing app?

This is a new app or experiment

Issue description and reproduction steps

.

Relevant code snippets

Expected behavior

No response

Identity provider

Microsoft Entra ID (Work and School accounts and Personal Microsoft accounts)

Regression

No response

Solution and workarounds

No response