Table loader fix

[vbaranov]

Motivation

Fix tokens list page table loader: number of columns in loader should match the number of columns in the table

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 b9848b44a2ca85a5086ffe7c3e56178232298a14-PR-3696

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.1%) to 64.643%

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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%
test/block_scout_web/features/pages/chain_page.ex	1	90.0%

Totals
Change from base Build 429b75e7d9acbdb053421ca3bd9d3d40d67472e2:	-1.1%
Covered Lines:	2108
Relevant Lines:	3261

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💛 - Coveralls