Turn off ILM policy name validation

I'm looking for ways to turn off the ILM policy name validation. Since it has no SRVxxxxxx code assigned, it cannot be covered as such in the validation.yml

Start by tracing the ILM policy name validation and how validation.yml handles policies without an SRVxxxxxx code. The issue names no source file or test, so locate the relevant validation entry point first. Done means the validation can be turned off for this case without requiring an SRV code.

Written by the indexing model from the issue text.