IDE0005 fix-all-in-solution erroneously removes imports from NuGets referenced via PackageReference in .NET Framework projects

The following issue was found via testing with `dotnet format` - if a .NET Framework project uses `PackageReference` to maintain NuGet references instead of `packages.config` ([MS doc ref](https://docs.microsoft.com/en-us/nuget/consume-packages/migrate-packages-config-to-package-reference)), any imports for namespaces from NuGet packages installed on that project will be erroneously deleted by the fix-all-in-solution function for IDE0005 (remove unnecessary import), causing the resulting edited project to fail to build due to missing imports.

Same problem is not present in .NET Framework projects using `packages.config` - in our case, however, it is not feasible to migrate back to `packages.config` due to `PackageReference` being a requirement for some of our dependencies (most notably Refit).

Note that this applies to .NET Framework generally and not just ASP.NET Framework - the same issue appears in .NET Framework Windows service projects, for example.

Potentially related: https://github.com/dotnet/format/issues/1061

**Version Used**: latest in Visual Studio 2022

**Steps to Reproduce**:

1. Open a .NET Framework solution using `PackageReference` instead of `packages.config` in Visual Studio 2022.
2. If not already installed, install the dotnet-format tool globally.
3. Run the following in the Package Manager Console: `dotnet format --severity info`

**Expected Behavior**: Only unused imports removed per IDE0005 analyser

**Actual Behavior**: Both unused imports _and_ imports for namespaces from NuGet packages removed per IDE0005 analyser