[8.x] Add search snapshot API examples (#3459)

[lcawl]

Backport

This will backport the following commits from main to 8.x:

• Add search snapshot API examples (#3459)

Questions ?

Please refer to the Backport tool documentation

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
searchable_snapshots.cache_stats	⚪	Missing test	Missing test
searchable_snapshots.clear_cache	🟢	1/1	1/1
searchable_snapshots.mount	🟢	4/4	4/4
searchable_snapshots.stats	🟢	1/1	1/1

You can validate these APIs yourself by using the make validate target.