Fix JSON conversion bug in template PUT endpoint

Fixed a bug where empty dictionaries for configurations, secrets, and schemas
were incorrectly converted to NULL in the database instead of empty JSON objects.

Changed the condition from 'if value' to 'if value is not None' for:
- configurations_json
- secrets_json
- expected_payload_schema_json
- expected_callback_response_schema_json

This ensures that:
- None → NULL in database (intended behavior)
- {} → "{}" (empty JSON object, now works correctly)
- {"key": "value"} → JSON string (continues to work)

The bug was causing configuration updates to fail silently when the resulting
dict was empty or falsy, as Python treats empty dicts as falsy.

https://claude.ai/code/session_01N3rCYzU3puAwWKG1mszpHh

Author: claude

app/database/accessor/breeze_buddy/template.py

@@ -105,19 +105,23 @@ async def create_template(
         # Convert flow to JSON string
         flow_json = json.dumps(flow)
         expected_payload_schema_json = (
-            json.dumps(expected_payload_schema) if expected_payload_schema else None
+            json.dumps(expected_payload_schema)
+            if expected_payload_schema is not None
+            else None
         )
         expected_callback_response_schema_json = (
             json.dumps(expected_callback_response_schema)
-            if expected_callback_response_schema
+            if expected_callback_response_schema is not None
             else None
         )
 
         # Convert configurations to JSON string
-        configurations_json = json.dumps(configurations) if configurations else None
+        configurations_json = (
+            json.dumps(configurations) if configurations is not None else None
+        )
 
         # Convert secrets to JSON string
-        secrets_json = json.dumps(secrets) if secrets else None
+        secrets_json = json.dumps(secrets) if secrets is not None else None
 
         query, values = create_template_query(
             template_id,
@@ -332,19 +336,23 @@ async def replace_template(
         # Convert flow to JSON string
         flow_json = json.dumps(flow)
         expected_payload_schema_json = (
-            json.dumps(expected_payload_schema) if expected_payload_schema else None
+            json.dumps(expected_payload_schema)
+            if expected_payload_schema is not None
+            else None
         )
         expected_callback_response_schema_json = (
             json.dumps(expected_callback_response_schema)
-            if expected_callback_response_schema
+            if expected_callback_response_schema is not None
             else None
         )
 
         # Convert configurations to JSON string
-        configurations_json = json.dumps(configurations) if configurations else None
+        configurations_json = (
+            json.dumps(configurations) if configurations is not None else None
+        )
 
         # Convert secrets to JSON string
-        secrets_json = json.dumps(secrets) if secrets else None
+        secrets_json = json.dumps(secrets) if secrets is not None else None
 
         query, values = replace_template_query(
             template_id,