security: remove unused rollup-plugin-serve (CVE-2020-7684) (#1077)

## Summary

- Removes `rollup-plugin-serve` from devDependencies — it was never used
in the codebase (`rollup-plugin-dev` serves the same purpose)
- Fixes SNYK-JS-ROLLUPPLUGINSERVE-585897 / CVE-2020-7684 (Directory
Traversal, CVSS 9.8)
- Also removes transitive dependencies `mime@3.0.0` and `opener@1.5.2`
which were only pulled in by this package

No functional impact.

Author: yogeshchoudhary147

package-lock.json

@@ -82,7 +82,6 @@
     "rollup-plugin-dev": "^1.1.3",
     "rollup-plugin-livereload": "^2.0.5",
     "rollup-plugin-peer-deps-external": "^2.2.4",
-    "rollup-plugin-serve": "^2.0.2",
     "rollup-plugin-typescript2": "^0.37.0",
     "start-server-and-test": "^2.0",
     "ts-jest": "^29.4.0",