Allow brackets for arrays for contract input data, fix decoding for multiple inputs

[vbaranov]

#3486

Motivation

1. https://gitter.im/poanetwork/blockscout?at=5fcdf6f567bf4438e12d0a52 internal server error when calling a method with multiple inputs

2. Square brackets are not allowed for an array input type. In order to provide the same experience for Remix users, it is suggested to allow square brackets.

Changelog

1. Fix input data processing
2. Allow square brackets for an array input type

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

[coveralls]

Pull Request Test Coverage Report for Build 4c3f9b3de404b97738c4dc812c24c8ae0f2d3af4-PR-3513

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 7 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.08%) to 66.828%

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Files with Coverage Reduction	New Missed Lines	%
lib/block_scout_web/controllers/chain/market_history_chart_controller.ex	1	78.57%
lib/block_scout_web/checksum_address.ex	6	55.56%

Totals
Change from base Build 2bcf1ceaad28781617445ee9f0e2f13c2f6f54cc:	-1.08%
Covered Lines:	2065
Relevant Lines:	3090

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💛 - Coveralls