Context:
Since OPT-4926 the new elasticsearch version migrated to in the context of https://ci.optimize.camunda.cloud/view/all/job/upgrade-performance-large-static-dataset/ is 7.5.0. However we encountered failures of this test due to unexpected snapshot "disappearence", see https://ci.optimize.camunda.cloud/view/all/job/upgrade-performance-large-static-dataset/952/console
The underlying issue is on the side of elastic https://github.com/elastic/elasticsearch/issues/50200 and got fixed with 7.5.1 by https://github.com/elastic/elasticsearch/pull/50202.

We thus should use 7.5.1 at least during the migration test.

AT:

• Elasticsearch 7.5.1 is used for the at least the data migration tests

Note:
The added complexity to use 7.5.1 only for migration testing might not be worth it, thus we raising minimum version to 7.5.1 overall might be the better compromise.