Enhance CI build detection for broader compatibility

Updates the condition for `ContinuousIntegrationBuild` to specifically check for `GITHUB_ACTIONS` or the generic `CI` environment variable. This ensures more reliable detection of continuous integration environments, particularly for GitHub Actions and other common CI hosts.

Author: dansiegel

src/Directory.Build.props

@@ -7,7 +7,8 @@
     <IsPackable Condition=" '$(IsWpfProject)' ">!$(DisableWpfPublish)</IsPackable>
     <IsPackable Condition=" '$(IsFormsProject)' ">!$(DisableFormsPublish)</IsPackable>
     <IsPackable Condition=" '$(IsUnoProject)' ">!$(DisableUnoPublish)</IsPackable>
-    <ContinuousIntegrationBuild Condition="'$(BUILD_BUILDID)' != ''">true</ContinuousIntegrationBuild>
+    <!-- GitHub Actions sets GITHUB_ACTIONS and CI; other CI hosts often set CI. -->
+    <ContinuousIntegrationBuild Condition="'$(GITHUB_ACTIONS)' == 'true' Or '$(CI)' == 'true'">true</ContinuousIntegrationBuild>
     <ImplicitUsings>enable</ImplicitUsings>
   </PropertyGroup>