Add retry mechanism to apt-get install in copi.owasp.org/Dockerfile

[abhijit9040]

Problem: During the build process for the Copi project, the apt-get install step occasionally fails due to transient network issues or temporary server timeouts (e.g., "mirror not found"). This causes the entire GitHub Actions pipeline to fail, requiring manual intervention to restart the build.

Reference Improvement File:
https://github.com/OWASP/cornucopia/pull/2111/changes/BASE..c9f9970545f12ced181833e547c84b6c5f1d4bf5#diff-7350ea8f0117a4e3b60093fff273a03f313ff9edc64ad153b9a953ad516906d2

Context: This improvement was originally suggested as part of my work on the Converter Pull Request (#2111).

[abhijit9040]

Hi @sydseter ,
Solution: Implement a retry block for the package installation steps. Specifically, if the first attempt fails, the system will sleep for 10 seconds, refresh the package list, and try again before giving up.

[sydseter]

I habe assigned you. Open separate pull-request for this.