fix: content-type is automatically set by lib

Author: nsklikas

src/charm.py

@@ -433,7 +433,6 @@ def _create_openfga_store(self, token: str, store_name: str):
 
         # to create a new store we issue a POST request to /stores
         # endpoint
-        headers["Content-Type"] = "application/json"
         response = requests.post(
             "{}/stores".format(address),
             json={"name": store_name},