[Feature Request] Expose WithAssertion at request level

[bgavrilMS]

MSAL client type

Confidential

Problem statement

Callbacks are hard and are making the flows in Identity.Web very tricky due to callback chaining.

Expose WithClientAssertion(string) or WithClientAssertion(ClientAssertion) at request level. This always overrides the app.

Proposed solution

No response

Alternatives

No response

[bgavrilMS]

CC @gladjohn

[gladjohn]

@bgavrilMS when do we need this?