fix: report absolute expected deposit index in ErrDepositIndexOutOfOrder

[rachit77]

Summary

• ValidateNonGenesisDeposits was logging i (the zero-based loop counter) as the expected deposit index in the ErrDepositIndexOutOfOrder error message instead of depositIndex+uint64(i) (the absolute eth1 deposit index from state)
• The validation logic itself was correct blocks were rejected properly only the diagnostic message was wrong
• A chain 100 deposits in would report "expected index: 0" instead of "expected index: 100"

Test

• Added TestDepositIndexOutOfOrderErrorMessage: seeds the deposit store with 6 entries, sets depositIndex=5 on the state directly, submits a deposit with index 0 (wrong), and asserts the error contains "expected index: 5" not "expected index: 0"

[Copilot]

Pull request overview

Fixes the ErrDepositIndexOutOfOrder diagnostic message in ValidateNonGenesisDeposits to report the absolute expected deposit index derived from the state (depositIndex + i) rather than the zero-based loop counter.

Changes:

• Update ValidateNonGenesisDeposits to format expected index as depositIndex+uint64(i).
• Add a regression test to assert the error message contains the absolute expected index.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
state-transition/core/validation_deposits.go	Fixes the wrapped error message to report the correct absolute expected deposit index.
state-transition/core/validation_deposits_test.go	Adds a regression test ensuring the error message includes the state-based expected index.

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[Copilot]

Redundant import alias: the imported package path ends in /state-transition/core and the package name is already core, so core ".../core" adds an unnecessary alias. This also deviates from existing usage in this repo (e.g., state-transition/core/core_test.go:38 imports it without an alias) and may be flagged by the importas linter in .golangci.yaml. Consider importing without the alias and keeping usages as core.<...> (they will continue to compile).

[rachit77]

fixed 1e9f395