Prepare release for networkcloud (Azure#49643)

Author: live1206

sdk/networkcloud/Azure.ResourceManager.NetworkCloud/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 1.2.0-beta.1 (Unreleased)
+## 1.2.0-beta.1 (2025-04-25)
 
 ### Features Added
 - This SDK version supports 2024-10-01-preview API version.
@@ -13,12 +13,6 @@
 - VirtualMachine is updated to support persistent storage for OS disk.
 - VirtualMachine's property VmDeviceModel gets a new option 'T3'. When 'T3' is selected, SecureBoot and vTPM are automatically enabled. This is to support Windows users.
 
-### Breaking Changes
-
-### Bugs Fixed
-
-### Other Changes
-
 ## 1.1.0 (2025-01-31)
 
 ### Features Added