Parse data.json with json.load() in explicit_encoding.py

Keeps data.json handling consistent with app_v1.py and app_v2.py across
the tutorial's examples. legacy.csv stays a raw read, since the point
there is the locale sentinel rather than parsing.

Author: lpozo

python315-utf8-default/explicit_encoding.py

@@ -1,5 +1,7 @@
+import json
+
 with open("data.json", encoding="utf-8") as f:  # Portable and unambiguous
-    data = f.read()
+    data = json.load(f)
 
 with open("legacy.csv", encoding="locale") as f:  # Intentional locale use
     legacy = f.read()