[Blazor] Update branding for the next release (#17852)

Author: javiercn

src/Components/Blazor/Directory.Build.props

@@ -3,8 +3,8 @@
 
   <PropertyGroup>
     <!-- Override version labels -->
-    <VersionPrefix>3.1.0</VersionPrefix>
-    <PreReleaseVersionLabel>preview4</PreReleaseVersionLabel>
+    <VersionPrefix>3.2.0</VersionPrefix>
+    <PreReleaseVersionLabel>preview1</PreReleaseVersionLabel>
     <DotNetFinalVersionKind />
     <!-- This property points to the latest released Microsoft.AspNetCore.App version it needs to be updated to
          target the latest patch before a preview release. -->