Refactor to use atomic types

[Sahil-4555]

What type of PR is this?

Other

What does this PR do? Why is it needed?
This PR updates our atomic operations to use Go 1.19's newer typed atomic approach instead of the old function-based method. We're changing fields like uint64 to atomic.Uint64 so we can write cleaner code like counter.Add(1) instead of atomic.AddUint64(&counter, 1). This removes the need for pointer handling and gives us better compile-time safety when multiple threads access the same variables in validator operations.

Which issues(s) does this PR fix?
The function-based atomics allowed accidental non-atomic access to shared variables, causing race conditions in concurrent validator operations. The verbose atomic.AddUint64(&counter, 1) syntax was harder to maintain. Typed atomics enforce atomic-only access at compile time and use cleaner method calls, preventing threading bugs in validator sync committee statistics where multiple goroutines update counters simultaneously.

Acknowledgements

• I have read CONTRIBUTING.md.
• I have included a uniquely named changelog fragment file.
• I have added a description to this PR with sufficient context for reviewers to understand this PR.

[prestonvanloon]

Changelog fragment is not in the correct format. Please reduce the language in the fragment as well. We use the fragments to create the changelog notes so your comment should be clear and concise.

[Sahil-4555]

Changelog fragment is not in the correct format. Please reduce the language in the fragment as well. We use the fragments to create the changelog notes so your comment should be clear and concise.

Changes Done.

[prestonvanloon]

Thanks!