Use non-optional UUID init for zero-IDFA sentinel

UUID(uuidString:) returns Optional, which would silently make the
equality check at the call site false if the literal ever failed to
parse — the zero-IDFA sentinel would then slip through unfiltered.
Switch to UUID(uuid:) which takes the 16-byte tuple directly and
returns a non-optional, removing the optionality from the comparison
without resorting to force-unwrap.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yusuftor

Sources/SuperwallKit/Analytics/Attribution/AttributionFetcher.swift

@@ -56,7 +56,10 @@ final class AttributionFetcher {
     return nil
   }
 
-  private static let zeroAdvertisingIdentifier = UUID(uuidString: "00000000-0000-0000-0000-000000000000")
+  // Non-optional construction via `init(uuid:)` — `init(uuidString:)` returns
+  // an Optional which would make the equality check silently false-positive
+  // if the literal ever failed to parse.
+  private static let zeroAdvertisingIdentifier = UUID(uuid: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
 
   /// Whether this build/environment can ever produce an AdServices token.
   /// `false` on builds that didn't link AdServices.framework and on debug