Remove mention of repositories.s3.base_path in doc (#69516)
Remove mention of repositories.s3.base_path in doc (#69516)

We removed the global `repositories.s3.base_path` setting in 6.0 but it
is still mentioned in the docs for the S3 repository plugin. This commit
removes it from the docs.

Relates #24445
GlenRSmith/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch