Event definition summary is confusing: correlation event #1 rule

When looking at the event definition summary, it is easy to get confused about a correlation rule.
Specifically, when the condition is that event #1 should occur **at least** n times, the summary will show `Should occur n times`. It is easy to think that this means exactly n times, rather than at least n times.

Modify the wording to say `Should occur at least n times`

## Context
This came up in an actual customer support ticket. Customer was not a novice, but they still failed to notice the distinction. This cost a fair amount of support time until it was clarified.

HS-439847458