Add Data Retention section to pricing calculator

Added a section on Data Retention in Logic Apps with details on default retention periods.

Author: brown9804

0_Azure/8_AzureApps/demos/3_LogicApps/1_LogicApps_pricing_calc.md

@@ -21,12 +21,15 @@ Last updated: 2025-10-23
 <details>
 <summary><b>Table of Content</b> (Click to expand)</summary>
 
+- [Data Retention](#data-retention)
 - [Consumption vs Standard](#consumption-vs-standard)
 - [Prices Vary by Region](#prices-vary-by-region)
 - [How to calculate it?](#how-to-calculate-it)
 
 </details>
 
+## Data Retention
+
 > [!TIP]
 > What is Data Retention in Logic Apps?
 > - Logic Apps stores run history, inputs, and outputs for troubleshooting and auditing. By default: