Verify eslint-env inline configuration comments/globals are still necessary

Before upgrading to ESLint v10 there will be a few warnings to look into. Apparently eslint-env comments in the webpack configs are still considered part of the eslintrc (non-flat) era:

ESLintEnvWarning: /* eslint-env */ comments are no longer recognized when linting with flat config and will be reported as errors as of v10.0.0. Replace them with /* global */ comments or define globals in your config file. See https://eslint.org/docs/latest/use/configure/migration-guide#eslint-env-configuration-comments for details.

Quickly checking I think these are already correctly configured in the right places from when Alex migrated to the new config style, so it may just be as simple as removing these remnants — but I'll cross-reference the values and environments first, to check it's actually 1:1 mapped already, or there are deviations worth mentioning.

Inspect the webpack configuration files and the current flat ESLint configuration. Cross-reference each eslint-env comment's environments and globals, remove only comments that are already represented elsewhere, and verify that the warnings no longer occur before the ESLint v10 upgrade.