integration tests with Node 20

[turadg]

What is the Problem Being Solved?

Node 20 is the Active LTS and our integration tests don't test it.

Description of the Design

The SDK's own tests now run Node 18 and 20:

• allow Node 20 #8920

But the integration tests with other repos are stuck one 16:

• drop tests for Node 16 #8638

Once we have 18 in the matrix, we can drop 16 which is EOL:

• drop Node 16 (EOL) #8365

But that's blocked on,

• feat(integration-test): use dapp-offer-up as target for getting-start… #8829

Security Considerations

Scaling Considerations

Test Plan

Upgrade Considerations