Support RFC 8693 token exchange for enterprise IdP flows (SEP-990) (#2988)

Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com>

src/mcp/server/mcpserver/server.py

@@ -964,6 +964,7 @@ class MCPServer(Generic[LifespanResultT]):
                         service_documentation_url=self.settings.auth.service_documentation_url,
                         client_registration_options=self.settings.auth.client_registration_options,
                         revocation_options=self.settings.auth.revocation_options,
+                        identity_assertion_enabled=self.settings.auth.identity_assertion_enabled,
                     )
                 )