Accept wider range of IOS timestamp formats

[candlerb]

(Note: it would be simpler to use .*\d*\s*\w* to capture optional milliseconds and timezone, but that pattern doesn't appear to work)

Fixes problem identified in https://github.com/wazuh/wazuh/issues/2399 and adds some test cases

[candlerb]

Rebased to current master

[Lopuiz]

Hello @candlerb

First, sorry for the late answer. Thank you for your contribution to the Ruleset project. I'm going to review your PR and give you an answer shortly.

Kind regards, Eva