chore: Migrate ESLint configuration file to new flat format. (#8675)

* chore: rename .eslintrc.js to eslint.config.js

* chore: Rename eslint.config.js to eslint.config.mjs.

* refactor: Migrate ESLint config to new flat format.

* chore: Remove old per-directory and global ignore ESLint config files.

* fix: Allowlist JSDoc tag aliases.

* fix: Don't require @license in tests/*.

* fix: Add NodeJS globals to several files that run under Node.

* chore: Remove now-unneeded ESLint directives in core.

* chore: Remove invalid/unneeded ESLint directives.

* fix: Fix invalid use of `await` outside of an `async` function.

* fix: Improve screenshot error message.

* fix: Update ESLint config file to not warn on existing violations.

* chore: Remove suppressions of rules that weren't triggering.

* chore: Fix package-lock.json.

core/interfaces/i_serializer.ts

@@ -30,7 +30,6 @@ export interface ISerializer {
    *     state to record.
    */
   save(workspace: Workspace): object | null;
-  /* eslint-enable valid-jsdoc */
 
   /**
    * Loads the state of the plugin or system.