Distro 1.6.8 Hotfix pin w/ changelog date (#40553)

* hotfix: pin OT 1.31.1/0.52b1

Author: jeremydvoss

sdk/monitor/azure-monitor-opentelemetry/CHANGELOG.md

@@ -1,14 +1,12 @@
 # Release History
 
-## 1.6.8 (Unreleased)
+## 1.6.8 (2025-04-17)
 
 ### Bugs Fixed
 
 - Pin OTel before breaking change.
     ([#40529](https://github.com/Azure/azure-sdk-for-python/pull/40529))
 
-### Other Changes
-
 ## 1.6.7 (2025-04-10)
 
 ### Bugs Fixed