Remove leftover references to IsExternalInit

src/MeidoPhotoStudio.Plugin/MeidoPhotoStudio.Plugin.csproj

@@ -28,10 +28,4 @@
             <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
         </Content>
     </ItemGroup>
-    <ItemGroup>
-      <PackageReference Include="IsExternalInit" Version="1.0.0">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
-    </ItemGroup>
 </Project>