fix(tests): update blob base cost in eip7918 spec to 2**13 (#1862)

Author: LouisTsai-Csie

tests/osaka/eip7918_blob_reserve_price/spec.py

@@ -24,7 +24,7 @@ class Spec(EIP4844Spec):
     Extends EIP-4844 spec with the new reserve price constant and functionality.
     """
 
-    BLOB_BASE_COST = 2**14
+    BLOB_BASE_COST = 2**13
 
     @classmethod
     def get_reserve_price(