Refine contract method signature detection for read/write feature

[vbaranov]

Motivation

Internal server error for reading method if ABI consists of multiple methods with the same name

Changelog

Replace function_name with method_id to a better search of the target method to call

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
• If I added/changed/removed ENV var, I submitted a PR to https://github.com/blockscout/docs to update the list of env vars at https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md and I updated the version to master in the Version column. Changes will be reflected in this table: https://docs.blockscout.com/for-developers/information-and-settings/env-variables.
• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools

[github-actions]

Pull Request Test Coverage Report for Build 76454ac0ca0873415646c6cc5a8c596c6bb83dc2-PR-3237

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-15.7%) to 55.793%

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Totals
Change from base Build a2a32489077a9e82f15b52fa4076128d7824d3a0:	-15.7%
Covered Lines:	443
Relevant Lines:	794

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💛 - Coveralls