feat: bring network fees to portals rates

[gomesalexandre]

Description

Precisely what it says on the box - Portals now returns gas limit on estimate calls (rates), we have a gas oracle for gas price, and the intersection of that is us able to get network fees for Portals rates 🎉

Issue (if applicable)

closes #8822

Risk

High Risk PRs Require 2 approvals

What protocols, transaction types, wallets or contract interactions might be affected by this PR?

None

Testing

• Portals rates now have network fees displayed

Engineering

• ^

Operations

• 🏁 My feature is behind a flag and doesn't require operations testing (yet)

• ^

Screenshots (if applicable)