This reverts commit 290720f.

Historically, the set of project properties we passed to Roslyn when initialising an `IWorkspaceProjectContext` was hard-coded in the project system. We changed this recently in dotnet#8499, and introduced a means for Roslyn to request whatever properties they wanted, allowing Roslyn to make changes without requiring a synchronised change in the project system.

With that change, we serviced property value requests using `ProjectRuleSource` data. This limited Roslyn to only those properties present in our `ConfigurationGeneral` XAML rule file.

This commit uses a `ProjectInstance` to service such requests instead. This means that Roslyn can add new projects in their own props/targets, and not need the project system to make any changes in order to provide those values.

Motivated by a bug exposed through dotnet/roslyn#64749 which added required property `OutputAssemblyForDesignTimeEvaluation` which did not exist in our rules, leading to runtime errors.

Historically, the set of project properties we passed to Roslyn when initialising an `IWorkspaceProjectContext` was hard-coded in the project system. We changed this recently in dotnet#8499, and introduced a means for Roslyn to request whatever properties they wanted, allowing Roslyn to make changes without requiring a synchronised change in the project system.

With that change, we serviced property value requests using `ProjectRuleSource` data. This limited Roslyn to only those properties present in our `ConfigurationGeneral` XAML rule file.

This commit uses a `ProjectInstance` to service such requests instead. This means that Roslyn can add new projects in their own props/targets, and not need the project system to make any changes in order to provide those values.

Motivated by a bug exposed through dotnet/roslyn#64749 which added required property `OutputAssemblyForDesignTimeEvaluation` which did not exist in our rules, leading to runtime errors.

Historically, the set of project properties we passed to Roslyn when initialising an `IWorkspaceProjectContext` was hard-coded in the project system. We changed this recently in dotnet#8499, and introduced a means for Roslyn to request whatever properties they wanted, allowing Roslyn to make changes without requiring a synchronised change in the project system.

With that change, we serviced property value requests using `ProjectRuleSource` data. This limited Roslyn to only those properties present in our `ConfigurationGeneral` XAML rule file.

This commit uses a `ProjectInstance` to service such requests instead. This means that Roslyn can add new projects in their own props/targets, and not need the project system to make any changes in order to provide those values.

Motivated by a bug exposed through dotnet/roslyn#64749 which added required property `OutputAssemblyForDesignTimeEvaluation` which did not exist in our rules, leading to runtime errors.

Historically, the set of project properties we passed to Roslyn when initialising an `IWorkspaceProjectContext` was hard-coded in the project system. We changed this recently in dotnet#8499, and introduced a means for Roslyn to request whatever properties they wanted, allowing Roslyn to make changes without requiring a synchronised change in the project system.

With that change, we serviced property value requests using `ProjectRuleSource` data. This limited Roslyn to only those properties present in our `ConfigurationGeneral` XAML rule file.

This commit uses a `ProjectInstance` to service such requests instead. This means that Roslyn can add new projects in their own props/targets, and not need the project system to make any changes in order to provide those values.

Motivated by a bug exposed through dotnet/roslyn#64749 which added required property `OutputAssemblyForDesignTimeEvaluation` which did not exist in our rules, leading to runtime errors.