Draws a URI as a QR code on the server, as an SVG data URI, so the portal needs no script.
the text to encode, usually from otpauthUri()
otpauthUri()
a promise of the data:image/svg+xml;base64, URI
data:image/svg+xml;base64,
Draws a URI as a QR code on the server, as an SVG data URI, so the portal needs no script.