Kibana version: 8.15+

Elasticsearch version: 8.15+

Description
Not sure if this is a bug or a feature request, or something in between. Synthetics recently got the ability to run monitors every 10s and 30s. The API currently allows values as numbers 1, 2, 3, 5, 10, 15, 20, 30, 60, 120, 240.

This creates two possible value strings that the API can accept. One a string with value either "10s" or "30s", or a number with one of the aforementioned values. This brings challenges when using it with our TF provider. Resulting in an error:

│ Error: Incorrect attribute value type
│
│   on modules/kibana/synthetics-icmp.tf line 30, in resource "elasticstack_kibana_synthetics_monitor" "icmp_test":
│   30:   schedule  = "10s"
│
│ Inappropriate value for attribute "schedule": a number is required.

Expected behavior:
It would be better if we could define the values in numbers entirely with 10s and 30s substituted as 0.1 and 0.3. This would keep the API type consistent and cleaner.