Remove running outside of distribution check
Remove running outside of distribution check

This commit removes a legacy check against running bin/elasticsearch
that is not produced from a distribution. This check exists for legacy
reasons, namely when bin/elasticsearch previously sat in the root of the
Elasticsearch repository. In this old scenario, someone might clone the
repository, see the bin folder and try to run bin/elasticsearch without
first production a distribution. Today, this is unlikely since
bin/elasticsearch now sits in
distribution/src/main/resources/bin/elasticsearch so first, bin is no
longer in the root of the repository, and second, the src indicates this
is source and not already for production. Moreover, our README in the
root of the repository provides clear instructions for getting started:
either download a distribution or build one from source. In the name of
simplicity, we therefore remove this legacy check.

Relates #25960

strapdata/elassandra,vroyer/elassandra,strapdata/elassandra,vroyer/elasticassandra,strapdata/elassandra,vroyer/elassandra,strapdata/elassandra,vroyer/elasticassandra,strapdata/elassandra,vroyer/elasticassandra,vroyer/elassandra