Update Staking DApp scripts due to MetaMask breaking changes

[varasev]

Motivation

There are MetaMask breaking changes: https://docs.metamask.io/guide/provider-migration.html

This PR uses the latest changes for Staking DApp JavaScript code.

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 0f8b91cc7ffe1f5760681986b284011c5b2db6c1-PR-3460

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 7 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.5%) to 67.103%

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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 84741f3db5aba428c7820153579840f2aa4e790a:	-1.5%
Covered Lines:	2052
Relevant Lines:	3058

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💛 - Coveralls

[vbaranov]

Approved with minor improvements suggestions

[varasev]

@vbaranov I made refactorings you proposed above in 2edb8ce.

[vbaranov]

Awesome. I notice that one more message could be placed into constants.