Fix literal from addresses in ETHTx tasks

[ChrisWozniak]

Fixes #21768

Requires

• None.

Supports

• None.

Summary

• Accept a literal EVM address for an ethtx task's from parameter.
• Preserve existing variable-expression and JSON-array from behavior.
• Add a regression case for the reported bare-address input.

Testing

• ./tools/test/.bin/test --ai-output -v -count=1 -run '^TestETHTxTask$' ./core/services/pipeline

Risk assessment

Low. The change is limited to ETHTxTask parameter resolution and is covered by the focused task suite.

Review focus

Please verify that literalAddressSlice recognizes only valid literal addresses and falls through to the existing JSON/variable resolvers for all other inputs.