feat: Send PII to Spotlight when no DSN is set

Quick fix for getsentry/spotlight#543 until we implement a global scrubber that only scrubs events sent to the clound thorugh the DSN.

Author: BYK

sentry_sdk/client.py

@@ -451,7 +451,11 @@ def should_send_default_pii(self):
 
         Returns whether the client should send default PII (Personally Identifiable Information) data to Sentry.
         """
-        return self.options.get("send_default_pii", False)
+        result = self.options.get("send_default_pii")
+        if result is None:
+            result = not self.options["dsn"] and self.spotlight is not None
+
+        return result
 
     @property
     def dsn(self):