fix: ESM-specific configuration bugs

[ehmicky]

We have just added an ESM-specific configuration file.

I tried to use the new exports feature which allows the import name to be different from the file path being imported. However, this seems to fail with ESLint and report a "module not found" error. When making the import name mirror the imported file path, this error disappears.

Also, when merging the base ESLint configuration, I forgot to merge its parserOptions.

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