Show brand icon instead of the Sparrow icon on direct feedback responses

As an admin-level user configuring Brand Settings, I need to specify the brand icon shown next to Direct Feedback Request responses, both in the Sparrow Intel portal and in the Sparrow Intel review widget embedded on my website. The icon shown should be that of the brand set on the Feedback Request.

Acceptance criteria

• Each brand in Brand Settings, including the default brand, can have its own square icon.

• In the portal, a direct feedback response shows the icon of the brand chosen on its feedback request.

• On a review widget, direct feedback responses show the icon of the brand selected for that widget.

• A brand without an icon keeps showing the current icon.