Fix incorrect version check order in MVVMToolkitRemoveDuplicateAnalyzers target

MSBuild PropertyGroup elements are evaluated top-to-bottom, with later
assignments overwriting earlier ones. The >= 4.12 check was before the
>= 4.3 check, so for any Roslyn version >= 4.12 (including 5.0), the
4.12 result would be immediately overwritten by the 4.3 match. This
caused the wrong analyzer (roslyn4.3) to be selected instead of the
correct one (roslyn4.12).

Swap the order so the lower version (4.3) is checked first and the
higher version (4.12) is checked last, ensuring the highest compatible
analyzer wins.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Sergio0694

src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.SourceGenerators.targets

@@ -86,8 +86,8 @@
       removes and removes all analyzers except the highest version that is supported. The fallback is just Roslyn 4.0.
     -->
     <PropertyGroup>
-      <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.12))">roslyn4.12</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
       <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.3))">roslyn4.3</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
+      <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.12))">roslyn4.12</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
       <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="'$(MVVMToolkitSelectedRoslynAnalyzerDirectoryName)' == ''">roslyn4.0</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
     </PropertyGroup>
     <ItemGroup>