`radius_testnet` has an invalid RPC URI

[emlautarom1]

Bug Description
The RPC URI listed in the radius_testnet configuration file lacks a scheme (http or https), thus causing issues when parsed. Specifically, C#'s Uri class fails to parse the provided URI due to the missing scheme:

superchain-registry/superchain/configs/sepolia/radius_testnet.toml

Line 3 in 6621a0f

sequencer_rpc = "dev-secure.rpc.theradius.xyz"

Steps to Reproduce

• Create a C# project or try it online: https://dotnetfiddle.net/
• Try to construct a URI through new Uri("dev-secure.rpc.theradius.xyz")

Expected behavior
The provided RPC URI should include the scheme to be used.

Environment Information:

• Dotnet version: 9.0.107