Function from_field_to_contact_id 

pub async fn from_field_to_contact_id(
    context: &Context,
    from: &SingleInfo,
    fingerprint: Option<&Fingerprint>,
    prevent_rename: bool,
    find_key_contact_by_addr: bool,
) -> Result<Option<(ContactId, bool, Origin)>>

Converts “From” field to contact id.

Also returns whether it is blocked or not and its origin.

• prevent_rename: if true, the display_name of this contact will not be changed. Useful for mailing lists: In some mailing lists, many users write from the same address but with different display names. We don’t want the display name to change every time the user gets a new email from a mailing list.

• find_key_contact_by_addr: if true, we only know the e-mail address of the contact, but not the fingerprint, yet want to assign the message to some key-contact. This can happen during prefetch. If we get it wrong, the message will be placed into the correct chat after downloading.

Returns None if From field does not contain a valid contact address.