Suppress 9 pre-existing ESLint/DeepSource sonarjs errors

[robin-the-going-merry]

Requested by: Michael Letellier

Surfaced while triaging failing e2e checks on #3378 (unrelated to that PR's own changes - these files aren't touched there). ESLint and DeepSource: JavaScript both fail the build on 9 pre-existing sonarjs errors. Decision: suppress rather than fix (Michael, 2026-09-18) - add an inline // eslint-disable-next-line <rule> (with a short reason comment) at each site below, not a global rule change in the eslint config:

• js/admin/legacy-views.js:398,401 - sonarjs/prefer-native-jquery-alternative
• js/admin/style.js:1238 - sonarjs/super-linear-regex
• js/formidable.js:896,2287,2549 - sonarjs/super-linear-regex
• js/src/admin/admin.js:9652 - sonarjs/prefer-native-jquery-alternative; :10511 - sonarjs/super-linear-regex
• js/src/admin/styles.js:83 - sonarjs/super-linear-regex

Once done, npx eslint should report 0 errors and DeepSource: JavaScript should pass, with the underlying jQuery/regex code left as-is.

[vivi-the-going-merry]

Fixed in #3387. All 9 sites confirmed clean (0 errors) via a standalone eslint+eslint-plugin-sonarjs@4.2.1 run against the current files; DeepSource: JavaScript passed.

One correction: the third super-linear-regex site is js/src/admin/admin.js:2549, not js/formidable.js:2549 — that file only has two (896, 2287).

Run ESLint overall still fails — 109 unrelated errors in tests/cypress/** (sonarjs/no-forced-browser-interaction, sonarjs/assertions-in-tests, sonarjs/prefer-specific-assertions), none in the 9 named files. [Likely] introduced by #3375's eslint-plugin-sonarjs 4.0.0→4.2.1 bump merged same day, outside this issue's scope.