fix(auth): prioritize first auth header

Author: stainless-app[bot]

src/onlyfansapi/_client.py

@@ -497,9 +497,11 @@ def qs(self) -> Querystring:
 
     @override
     def _auth_headers(self, security: SecurityOptions) -> dict[str, str]:
-        return {
-            **(self._default if security.get("default", False) else {}),
-        }
+        headers: dict[str, str] = {}
+        if security.get("default", False):
+            for key, value in self._default.items():
+                headers.setdefault(key, value)
+        return headers
 
     @property
     def _default(self) -> dict[str, str]:
@@ -959,9 +961,11 @@ def qs(self) -> Querystring:
 
     @override
     def _auth_headers(self, security: SecurityOptions) -> dict[str, str]:
-        return {
-            **(self._default if security.get("default", False) else {}),
-        }
+        headers: dict[str, str] = {}
+        if security.get("default", False):
+            for key, value in self._default.items():
+                headers.setdefault(key, value)
+        return headers
 
     @property
     def _default(self) -> dict[str, str]: