Skip the log-start aura snapshot while unit auras are restricted

[KogasaPls]

Starting a log in an active M+ (or any other content with aura restrictions) errors since 12.1:

GetAuraDataByIndex(): Auras cannot be accessed when secret while tainted by 'Transcriptor'

12.1 added RequiresUnitAuraAccess to the aura enumeration APIs, so they now throw for tainted code under restrictions instead of returning secret values, and the issecretvalue checks inside the snapshot loop never run. The error aborts StartLog after event registration, so recording continues but the "Beginning Transcript" print never appears and StartLog returns nothing to its caller.

This skips the snapshot when C_Secrets.ShouldAurasBeSecret() returns true. The function exists since 12.0, with a fallback for classic clients that lack C_Secrets. Skipping loses nothing: the data is unobtainable in that state anyway. Verified in-game in a key (enumeration throws and the predicate is true, both in and out of combat) and in open world (enumeration works and the predicate is false).