[Question]: Default time unit for `Ignore events older than` under datasets for System integration.

**Description:**
While validating https://github.com/elastic/integrations/issues/3149 we have observed that we are able to save `Ignore events older than` field with no time units( "ns", "us" (or "µs"), "ms", "s", "m", "h") defined.

**Question:**
If user saves this field with only numerical data, could you please confirm what would be the default time unit for `Ignore events older than` field?

**Screen Recording:**

https://user-images.githubusercontent.com/77374876/183611674-a6fdb3f4-60a8-463f-810e-8514dd24144a.mp4