[3.x] DownstreamApi: ignore caller-supplied reserved or duplicate headers in ExtraHeaderParameters#3806

Avery-Dunn merged 1 commit intorel/3vAzureAD/microsoft-identity-web:rel/3vfrom

avdunn/3.x-cherrypick-3793AzureAD/microsoft-identity-web:avdunn/3.x-cherrypick-3793Copy head branch name to clipboard