[Identity] Prepare 1.15.0 release (#51817)

Author: JonathanCrd

sdk/identity/Azure.Identity/CHANGELOG.md

@@ -1,8 +1,6 @@
 # Release History
 
-## 1.15.0-beta.2 (Unreleased)
-
-### Features Added
+## 1.15.0 (2025-08-07)
 
 ### Breaking Changes
 

sdk/identity/Azure.Identity/src/Azure.Identity.csproj

@@ -2,7 +2,7 @@
   <PropertyGroup>
     <Description>Provides APIs for authenticating to Microsoft Entra ID</Description>
     <AssemblyTitle>Microsoft Azure.Identity Component</AssemblyTitle>
-    <Version>1.15.0-beta.2</Version>
+    <Version>1.15.0</Version>
     <!--The ApiCompatVersion is managed automatically and should not generally be modified manually.-->
     <ApiCompatVersion>1.14.2</ApiCompatVersion>
     <PackageTags>Microsoft Azure Identity;$(PackageCommonTags)</PackageTags>