Backend: Remove json.pipeline_includes_count logging

In !108280 (merged), we introduced logging the metric json.pipeline_includes_count to monitor the total number of includes per pipeline creation. This log was used in the evaluation of the fix for Backend: Prevent unlimited number of includes f... (#367150 - closed)

You can view the logs in Elastic.

Proposal

In this issue, we aim to remove this logging after a sufficient monitoring period or when we deem it's no longer necessary. There are some issues related to the includes limits, in addition to #367150 (closed), that may benefit from this log.

Implementation

backend	MR
Remove CI json.pipeline_includes_count logging	!130374 (merged)