build(eslint-config-fluid): remove unused Rushstack plugins

[tylerbutler]

These plugins are no longer used after migrating to TypeScript ESLint v8
and community-maintained alternatives.

Blocked by

• build(eslint-config-fluid): migrate from eslint-plugin-import to eslint-plugin-import-x #25661 (migrate import plugin)
• build(eslint-config-fluid): migrate to @eslint-community/eslint-plugin-eslint-comments #25662 (migrate eslint-comments)
• build(eslint-config-fluid): update TypeScript ESLint to v8 #25663 (update TypeScript ESLint)
• build(eslint-config-fluid): migrate @rushstack/no-new-null to @typescript-eslint/no-restricted-types #25664 (migrate rushstack no-new-null)
• build(eslint-config-fluid): update unicorn and jsdoc plugins #25665 (update minor dependencies)

[Copilot]

Pull Request Overview

Removes unused Rushstack ESLint plugins from the eslint-config-fluid package dependencies after migrating to TypeScript ESLint v8 and community-maintained alternatives.

• Removed three Rushstack dependencies: eslint-patch, eslint-plugin, and eslint-plugin-security
• Clean up dependencies that are no longer needed after migration to newer ESLint ecosystem