docs: update to show missing price fields as absent instead of null

- Changed JSON example to show fields as absent rather than null
- Updated callouts to reflect that fields are missing/absent
- Clarified that price fields may be omitted from response when not computable

Co-Authored-By: Nidhi Singh <[email protected]>

Author: devin-ai-integration[bot]

pages/lazer/payload-reference.mdx

@@ -80,12 +80,8 @@ Here's what a typical StreamUpdated response that contains a PriceFeed looks lik
       },
       {
         "priceFeedId": 3,
-        "price": null,
-        "bestBidPrice": null,
-        "bestAskPrice": null,
         "publisherCount": 5,
-        "exponent": -8,
-        "confidence": null
+        "exponent": -8
       }
     ]
   },
@@ -97,9 +93,10 @@ Here's what a typical StreamUpdated response that contains a PriceFeed looks lik
 ```
 
 <Callout type="info">
-  In the example above, the third price feed shows `"price": null`, indicating
-  that the price could not be computed. When you encounter null values, use the
-  last valid price or wait for the next update.
+  In the example above, the third price feed has the `price`, `bestBidPrice`,
+  `bestAskPrice`, and `confidence` fields absent, indicating that these values
+  could not be computed. When you encounter missing price fields, use the last
+  valid price or wait for the next update.
 </Callout>
 
 <Callout type="warning">
@@ -131,12 +128,11 @@ Main aggregate price calculated from all contributing publishers
 - **Invariants**: Non-zero when present (null values filtered out)
 
 <Callout type="warning">
-  **Null Price Values**: In some cases, you may receive a `null` value for the
-  `price` field (shown as `"price": null` in JSON). This indicates that the
-  price could not be computed at that moment. When this occurs, you should
-  either use the last valid price you received or wait for a fresh update with a
-  valid price. Note that you may not always receive a price update in the
-  response if no valid price is available.
+  **Missing Price Fields**: In some cases, the `price` field (and related
+  optional fields like `bestBidPrice`, `bestAskPrice`, and `confidence`) may be
+  absent from the response. This indicates that the price could not be computed
+  at that moment. When this occurs, you should either use the last valid price
+  you received or wait for a fresh update with a valid price.
 </Callout>
 
 #### Data Publisher Count - `publisher_count`