Add workaround for dotnet watch in npmproj

[captainsafia]

Since we include a reference to the Microsoft.AspNetCore.Components.Web.JS.npmproj in the BasicTestApp, attempting to run dotnet watch run there raises the following exception because it cannot resolve the correct targets in all the referenced projects.

watch : MSBuild output from target 'GenerateWatchList':
watch : 
watch :    Build started 2/22/2021 1:33:02 PM.
watch :         1>Project "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/test/testassets/BasicTestApp/BasicTestApp.csproj" on node 1 (GenerateWatchList target(s)).
watch :         1>Project "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/test/testassets/BasicTestApp/BasicTestApp.csproj" (1) is building "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/Web.JS/Microsoft.AspNetCore.Components.Web.JS.npmproj" (3) on node 3 (_CollectWatchItems target(s)).
watch :         3>_CheckForInvalidConfiguration:
watch :             node -v
watch :         3>/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/Web.JS/Microsoft.AspNetCore.Components.Web.JS.npmproj : error MSB4057: The target "_CollectWatchItems" does not exist in the project.
watch :         3>Done Building Project "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/Web.JS/Microsoft.AspNetCore.Components.Web.JS.npmproj" (_CollectWatchItems target(s)) -- FAILED.
watch :         1>Done Building Project "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/test/testassets/BasicTestApp/BasicTestApp.csproj" (GenerateWatchList target(s)) -- FAILED.
watch :    Build FAILED.
watch :           "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/test/testassets/BasicTestApp/BasicTestApp.csproj" (GenerateWatchList target) (1) ->
watch :           "/Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/Web.JS/Microsoft.AspNetCore.Components.Web.JS.npmproj" (_CollectWatchItems target) (3) ->
watch :             /Users/captainsafia/github.com/dotnet/aspnetcore/src/Components/Web.JS/Microsoft.AspNetCore.Components.Web.JS.npmproj : error MSB4057: The target "_CollectWatchItems" does not exist in the project.
watch :        0 Warning(s)
watch :        1 Error(s)
watch :    Time Elapsed 00:00:03.93

We workaround this by adding an empty <Target Name="_CollectWatchItems" /> to the npmproj. Viola! dotnet watch run in the BasicTestApp works.

[ghost]

Hello @captainsafia!

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