Fix Safe Links policy-to-rule matching

[moorereason]

ORCA was failing on check 113 (Do not let users click through safe links to original URL), but the online Configuration Analyzer wasn't showing an issue. While looking into that issue, I noticed that ORCA said our custom Safe Links policy Does not apply. This PR resolves the issue for me, but I don't know about the ramifications for the rest of the package. PTAL

The underlying issue is that our custom Safe Links policy and rule don't always have the same name (similar to the Preset policies, according to your code comments). Not sure how we got into that situation.

Context:

PS> Get-SafeLinksRule | Select Name,SafeLinksPolicy,State |fl

Name            : Recommended safe links rule
SafeLinksPolicy : Recommended safe links policy
State           : Enabled