[UA] Increase robustness around ES deprecation message parsing

[sebelga]

When reviewing #119745 I realised that we have a logic in place to enhance the deprecation by parsing the string message returned by ES. It seems that this area of the code is bridle as our server side getCorrectiveAction method does not have API integration tests around it. We wouldn't be alerted of regression in the UI whenever ES decides to update their message.

In the linked PR we can see that there are 2 places with the same logic to detect if the deprecation message is related to ML (return /[Mm]odel snapshot/.test), I think it would be good to centralise the parsing logic in a single place and add comments. Ideally we would receive meta data from ES, but meanwhile we use regex to parse a string and enhance the deprecations it would be good to do it in a single place.

[elasticmachine]

Pinging @elastic/kibana-stack-management (Team:Stack Management)

[alisonelizabeth]

Ideally we would receive meta data from ES

Agreed. I found a similar bug caused by changed deprecation messages in #123501. ES did add this capability to an extent via elastic/elasticsearch#73089, but would likely need to build upon this.