Previously, if a health's details contained a key named status (either
because an indicator bean was named statusHealthIndicator or an
indicator added an entry named status to its details) this would
clash with the health's own status as the details were serialized as
siblings of the status field.

This commit updates Health to remove @JsonAnyGetter from getDetails().
This means that all of a Health's details will now be nested within
a separate details field, thereby preventing a possible clash with
the status field.

Closes gh-10249