Prysm v7.1.8 Patch Fixes Attestations, Adds Gloas Prep

Prysm v7.1.8 released, a highly recommended patch. Fixes libp2p propagation of early attestations and gRPC validator attestation issues. Builder client now auto-falls back to JSON when SSZ is rejected (415/406). Adds Gloas fork prep: partial data columns and progressive merkleization, plus geth v1.17.4 and go 1.26.5 upgrades.