Please see correction, I ran `apt autoremove` and then restarted.
bridge-utils was not automatically removed during the installation, it was after running `apt autoremove`
> Package: upgrade-reports
>
> Version: buster
>
> My system has a bridge interface configured in /etc/network/interfaces.
> I upgraded from stretch to buster. After the successful upgrade in
> the list of packages to be auto-removed is bridge-utils.
>
> "The following packages were automatically installed and are no longer required:
> bridge-utils..."
>
> After running `sudo apt autoremove` and a subsequent restart,
> the host was missing its bridge interfaces.
>
> Manual installation of bridge-utils fixed the network interfaces.
>
> I suppose bridge-utils did not have any dependencies which was why it
> was auto-removed but this is an important package since loss of
> connectivity can occur if upgrading remotely.
>
> Thank you,
>
> -Brenden