docs: document OCSF actor type_id changes and new event classes - #511

Running Vale across on the following files affected by this PR:

- product/admin/system-log.mdx

Attempting to initialize Vale linter...
No customer vale configuration detected. Using Mintlify's default configuration.
Attempting to run Vale spellcheck...
Vale spellcheck completed successfully.

product/admin/system-log.mdx:
	- 14:41     Did you really mean 'Cybersecurity'?
	- 14:135    Did you really mean 'Splunk'?
	- 56:19     Did you really mean 'Datasource'?
	- 72:115    Did you really mean 'datasource'?
	- 87:228    Did you really mean 'alertable'?
	- 91:29     Did you really mean 'Cybersecurity'?
	- 93:6      Did you really mean 'activity_id'?
	- 93:27     Did you really mean 'activity_id'?
	- 108:3     Did you really mean 'type_id'?
	- 126:3     Did you really mean 'class_uid'?
	- 133:57    Did you really mean 'fallthrough'?


Found 11 suggested changes across 1 files in 780.51ms