Revert Ponder prefetch optimization when possible

[shrugs]

see #1982 and #2016 for context

• wait until this is fixed upstream in ponder core, either:
  • a) CAIP-style ids are supported or, preferably,
  • b) ponder allows users to configure prefetch key builders per-event and we can describe the relationships between event args and keys to avoid this issue
    • this would allow us to remove the migrated_nodes parallel index optimization
    • as well as supporting the *_events join tables which have a similar problem

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• basically just revert perf(ensindexer): unblock Ponder prefetch on hot tables #2016

[coderabbitai]

🔗 Related PRs

#1820 - Disable byName index on subgraph_domains table [merged]

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