expose dns load balancing options through c bridge

[robcao]

What was changed

Added TemporalCoreClientDnsLoadBalancingOptions to the C bridge, so that users of the C bridge can set these options how they need

Why?

Users of the C bridge want to be able to change the dns load balancing options

Checklist

1. Closes

#1250

3. How was this tested:

Consumed this change in the .NET SDK: temporalio/sdk-dotnet#676

Verified all tests pass (both cargo test in this repository, and dotnet test in the dotnet-sdk`)

4. Any docs updates needed?

[Sushisource]

Thanks!

[Sushisource]

Looks like this just needs a cargo fmt @robcao

[robcao]

woops, done

[jmaeagle99]

I think this should drop the enabled fields in favor of breaking the default behavior for a cleaner design such that passing null actually means disabled (instead of default behavior) and push the default behavior up to the lang SDK layers, just like in temporalio/sdk-python#1501. @Sushisource, what do you think?

[robcao]

I'll be on vacation until June 8, so I created another commit with the alternate approach dropping the enabled field: robcao@497a98e

Feel free to use that instead (or to re-create the change, or I could also pick this up when I return)

[jmaeagle99]

Thank you for bringing the issue to our attention and proactively providing a fix.

I ended up reimplementing the change in #1267 without the enabled field and aligned it with the behavior of the other SDKs. I'll close out this PR at this time since it has been superseded.