Drop named-fork entries from EL blob schedule (geth 1.17.5 compat)

[barnabasbusa]

Summary

go-ethereum v1.17.5 removed the named-hardfork fields (Osaka, Amsterdam, UBT) from params.BlobScheduleConfig (ethereum/go-ethereum#35029 "Remove named hardforks from the BPO schedule"). Named forks no longer carry their own blob schedule; they inherit from the BPO chain below them.

This PR removes the three rows referencing those fields from the fork table in GetFullBlobSchedule (clients/execution/chainstate.go), keeping Cancun, Prague, and BPO1-5. It still compiles against the currently-pinned v1.17.4 and unblocks the dora side of the dependabot bump in #814.

Why this is behavior-safe

Both consumers of GetFullBlobSchedule are unaffected:

• GetBpoForks (services/chainservice_forks.go) only uses entries with IsBpo == true; the removed rows were all non-BPO.
• GetBlobScheduleForTimestamp picks the last entry before a timestamp. Under geth's new model a named fork never changes blob params — its schedule always equals the preceding BPO/Prague/Cancun entry — so those rows were redundant duplicates.

Notes

The go-ethereum bump itself is not included here; it remains blocked on an ethcore update for geth 1.17.5, which is in progress separately.

[barnabasbusa]

Closing in favor of #814, which now carries this change (the blob-schedule fix branch was merged into the dependabot branch there).