Upgrade Bitnami MongoDB to 16.x.x & Update dependency to use OCI registry

[Jonsy13]

Today, Litmus Helm-Chart uses 12.x.x version of Bitnami MongoDB which is now archived & but available via archived index. Bitnami has also moved to OCI registry from charts.bitnami.com for distributing charts for all it's packages.

Latest version provided by Bitnami for mongo is 16.x.x.

We should upgrade to the latest version & also update the registry.
This will need changes in dependency configs & also complete testing.

Related Links -

• https://blog.bitnami.com/2024/10/bitnami-helm-charts-moving-to-oci.html
• [Bitnami] Webiste https://charts.bitnami.com/bitnami is not accessible bitnami/charts#31053
• 🔊 Transitioning Bitnami Helm charts to OCI for enhanced security, efficiency, and compatibility bitnami/charts#30110