[Website]: Highlight that in case of Tail Based Sampling is enabled, what is the path/mount to be given free space

### Type of issue

None

### What documentation page is affected

https://www.elastic.co/docs/solutions/observability/apm/apm-server/installation-layout

### What happened?

It is not fully clear what is the mount point/path for using TBS when using APM Server/Integration.
In particular, it would be super handy for users running EA on container. If a user wants to use a persistent volume for TBS, we should tell in the docs, maybe as a snippet to add on top of https://www.elastic.co/docs/reference/fleet/elastic-agent-container#:~:text=Running%20Elastic%20Agent%20on%20a%20read%2Donly%20file%20system

### Additional info

_No response_