Bugfix: Add safe navigation operator on LoginHistory from authSession records

[camillerev]

I met the issue when the user has no LoginHistory in AuthSession (when we use the feature "login as portal user" for exemple).
We have the following error:

17:09:37.111 (8860793657)|FATAL_ERROR|System.NullPointerException: Attempt to de-reference a null object

Class.LogEntryEventBuilder.setQueriedAuthSessionDetails: line 983, column 1
Class.LogEntryEventBuilder.getLogEntryEvent: line 831, column 1
Class.Logger.saveLog: line 3722, column 1
Class.Logger.saveLog: line 3681, column 1

This issue occurs since the changes done in getAuthSessionProxies on this PR #813

To solve the issue I added safe navigation operators on LoginHistory from authSession records.

[jongpie]

Hi @camillerev thanks so much for submitting this PR, and apologies for my delay in reviewing it! Your changes look great - I'm going to push a few more commits to add some related tests, and to fix another issue I noticed when reviewing this. I'm hoping to merge this today or tomorrow.

[jongpie]

@camillerev I've published this as release v4.15.5 🎉 Thanks again for your work on this!