Fix version string truncation while generating cache_key

[nkitsaini]

Summary

Follow up for #11738

I missed this while reviewing the truncation changes.

format!("{:.N}", value) only truncates if the fmt::Display implementation supports it (by reading f.precision() in trait implementation).

So in our case format!("{:.N}", version.to_string()) will work but not format!("{:.N}", version) unless Version supports it.

Since we only need it once, I am just truncating after the string is created.

Test Plan

[charliermarsh]

Thanks.