Observe only sum and count in pipeline creation

What does this MR do and why?

Related to Pipeline step log entries have too many fields (#371636 - closed)

The pipeline creation logger currently logs too many fields to Elasticsearch causing performance and stability issues to the stack. We need to reduce the number of fields and remove those that are not essential.

For each observation we were logging count, max, min, sum and avg. In this MR we are removing min and avg, leaving sum (the overall duration), count (to understand the number of observations that contributed to sum) and max to understand the outreach of each repeated operation.

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