Enable debug logging from middleware in --verbose mode

[tmat]

Automatically include middleware log messages in the output of dotnet watch --verbose:

dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BlazorWasmHotReloadMiddleware[0]
      Middleware loaded
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Middleware loaded. Script /_framework/aspnetcore-browser-refresh.js (16067 B).
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Middleware loaded. Script /_framework/blazor-hotreload.js (799 B).
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[0]
      Middleware loaded
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Script injected: /_framework/aspnetcore-browser-refresh.js

Set DOTNET_MODIFIABLE_ASSEMBLIES even for client-only Blazor WASM apps (revert to behavior prior to 0c37ca5).

[dotnet-policy-service]

Thanks for your PR, @tmat.
To learn about the PR process and branching schedule of this repo, please take a look at the SDK PR Guide.

[tmat]

@phil-allen-msft ptal

[tmat]

@MackinnonBuck ptal