Tool install seems to fail when installing a multi-targeted tool for a specific framework when other frameworks in the package are missing

[baronfel]

Describe the bug

Details are at fsprojects/FSharpLint#748, will fill in later - but this does appear to be an actual problem in our logic. We can't seem to install a lower-TFM-than-expected tool.

To Reproduce

The assets are downloadable at https://github.com/fsprojects/FSharpLint/actions/runs/16333319389/artifacts/3550501863 - extract this and attempt to install the tool with a command like:

dotnet tool install --global dotnet-fsharplint --add-source ./artifacts --prerelease --framework net8.0 -v d

Exceptions (if any)

[NuGet Manager] [Info]   GET https://api.nuget.org/v3/registration5-gz-semver2/dotnet-fsharplint/index.json
[NuGet Manager] [Info]   OK https://api.nuget.org/v3/registration5-gz-semver2/dotnet-fsharplint/index.json 51ms
[NuGet Manager] [Info]   GET https://api.nuget.org/v3/registration5-gz-semver2/dotnet-fsharplint/index.json
[NuGet Manager] [Info]   OK https://api.nuget.org/v3/registration5-gz-semver2/dotnet-fsharplint/index.json 45ms
[NuGet Manager] [Info]   GET https://api.nuget.org/v3-flatcontainer/dotnet-fsharplint/index.json
[NuGet Manager] [Info]   OK https://api.nuget.org/v3-flatcontainer/dotnet-fsharplint/index.json 39ms
[NuGet Manager] [Info]   GET https://api.nuget.org/v3-flatcontainer/dotnet-fsharplint/0.25.1--date20250716-1121.git-1447adf/dotnet-fsharplint.0.25.1--date20250716-1121.git-1447adf.nupkg
[NuGet Manager] [Info]   OK https://api.nuget.org/v3-flatcontainer/dotnet-fsharplint/0.25.1--date20250716-1121.git-1447adf/dotnet-fsharplint.0.25.1--date20250716-1121.git-1447adf.nupkg 574ms
Skipping NuGet package signature verification.
Tool 'dotnet-fsharplint' failed to update due to the following:
The settings file in the tool's NuGet package is invalid: Settings file 'DotnetToolSettings.xml' was not found in the package.
Tool 'dotnet-fsharplint' failed to install. Contact the tool author for assistance.
Error: Process completed with exit code 1.

Further technical details

• Include the output of dotnet --info
• The IDE (VS / VS Code/ VS4Mac) you're running on, and its version

[marcpopMSFT]

@xperiandri we can't reproduce this at the moment. Do you have more details on what the configuration was that you tried it on? We've tried 8.0.4xx and net10 preview7

[xperiandri]

Do you mean it installs without the framework flag?