dotnet format does not use custom .editorconfig in 9.0.301

### Describe the bug
The command dotnet format does not work correctly in `> 9.0.301`

```
dotnet format xxx --no-restore --verify-no-changes
```

It appears that it no longer uses the `.editorconfig` file.

We have projects with dotnet build 8.0x, 9.x. They worked fine until the last versions

See, for example:
https://github.com/rabbitmq/rabbitmq-amqp-dotnet-client/actions/runs/15584250952

✅ Ubuntu uses `8.0`
🚫 Windows uses `9.0.300` ( it worked with `9.0.202` )

### To Reproduce

### Exceptions (if any)

It worked on my Mac with `9.0.202`, but now with `9.0.301`, it no longer works.

### Further technical details
```
.NET SDK:
Version: 9.0.301
Commit: a596cd22e2
Workload version: 9.0.300-manifests.9bcbba73
MSBuild version: 17.14.5+edd3bbf37

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.5
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.301/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.6
Architecture: arm64
Commit: 3875b54e7b

.NET SDKs installed:
8.0.201 [/usr/local/share/dotnet/sdk]
9.0.202 [/usr/local/share/dotnet/sdk]
9.0.301 [/usr/local/share/dotnet/sdk]
```

So, same error in the Ci and Mac locally.

```
dotnet format rabbitmq-amqp-dotnet-client.sln --no-restore --verify-no-changes
/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/IBackoffDelayPolicy.cs(40,27): error IDE1006: Naming rule violation: Missing prefix: 's_' [/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/RabbitMQ.AMQP.Client.csproj]
/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/IBackoffDelayPolicy.cs(41,27): error IDE1006: Naming rule violation: Missing prefix: 's_' [/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/RabbitMQ.AMQP.Client.csproj]
/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/Impl/AmqpManagement.cs(34,30): error IDE1006: Naming rule violation: Missing prefix: 's_' [/a/rabbitmq-amqp-dotnet-client/RabbitMQ.AMQP.Client/RabbitMQ.AMQP.Client.csproj]
```

it seems that it ignores `.editorconfig`

thank you