Merged PR 630435: [VS17.8] Version bump

We're doing a version bump so all branches have up-to-date opt-prof runs.

[Opt-prof version](https://dev.azure.com/devdiv/_apps/hub/ms-vscs-artifact.build-tasks.drop-hub-group-explorer-hub?name=OptimizationData/DotNet-msbuild-Trusted/internal/vs17.8/20250416.5/11417138/1)

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#### AI description  (iteration 1)
#### PR Classification
Version update.

#### PR Summary
This pull request updates the version prefix in the project configuration.
- `eng/Versions.props`: Updated `<VersionPrefix>` from `17.8.28` to `17.8.29`.
<!-- GitOpsUserAgent=GitOps.Apps.Server.pullrequestcopilot -->

Author: Mariana Dematte

eng/Versions.props

@@ -2,7 +2,7 @@
 <!-- Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the MIT license. See License.txt in the project root for full license information. -->
 <Project>
   <PropertyGroup>
-    <VersionPrefix>17.8.28</VersionPrefix>
+    <VersionPrefix>17.8.29</VersionPrefix>
     <DotNetFinalVersionKind>release</DotNetFinalVersionKind>
     <PackageValidationBaselineVersion>17.7.0</PackageValidationBaselineVersion>
     <AssemblyVersion>15.1.0.0</AssemblyVersion>