[Feature request]: Support Portal Link Customisation.

[subomi]

Is your feature request related to a problem? Please describe.

Right now, users are stuck with our portal link design. They'd like to customise it to fit their dashboard experience.

Describe the solution you'd like

We should design two solutions (via the embedded iframe and a headless React SDK) that enable users to customise the experience with the Portal Link's font, colour and logo.