Streamline MaxPipeline check for LogPipeline

[a-thaler]

Description
The max pipeline check for LogPipelines is executed as part of the validating webhook. For TracePipeline and MetricPipeline it is executed as a reconciler activity with proper status on the CR.

Goal: Use the same approach for all pipelines and remove unneeded code

Criteria:

• If a pipeline gets added which exceeds the max pipeline threshold, the pipeline never gets active
• The approach is streamlined across the pipeline types

[github-actions]

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