Update Postman collection

[m4sterbunny]

Postman collection should NOT support deprecated chains such as:

Holesky
Mordor
ETH Classic

• certain EEA/PRIV/PoW methods
• link to the docs that was 404

Status as of 20251126: simon.dudley as a reviewer to the PR https://www.postman.com/galactic-station-377443/besu-public-workspace/pull-request/e[…]9-e52497b136ab?workspace=0f9d184b-938b-4c02-9ad1-42c220105c46

Relates to issue: #1861

[m4sterbunny]

@macfarla can I close this given decision to retain deprecated items?