metrics: shotover_transform_total_count -> shotover_transform_success_count

[rukai]

Currently we have our metrics split up like this:

• shotover_transform_total_count
• shotover_transform_failures_count

where failures_count is a subset of total_count.

I think it would be more intuitive if had them disjoint like:

• shotover_transform_success_count
• shotover_transform_failures_count