op-deployer: standard.go contract tags should not carry -rc.N suffixes

Several `ContractsV*Tag` constants in `op-deployer/pkg/deployer/standard/standard.go` pin release-candidate tags rather than finalized releases (currently v1.8.0-rc.4, v4.0.0-rc.7, v6.0.0-rc.2, v7.0.0-rc.4, and now v8.0.0-rc.3). Once a contracts release is finalized, the constant should be updated to the final `op-contracts/vX.Y.Z` tag, which also requires the corresponding entries in the superchain-registry standard-versions files.

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Start in op-deployer/pkg/deployer/standard/standard.go and inspect the ContractsV*Tag constants listed in the issue. Then compare the corresponding entries in the superchain-registry standard-versions files, identify the finalized op-contracts tags, and update both locations so no listed contract tag retains an -rc.N suffix.

Written by the indexing model from the issue text.