Update the Blazor CRUD scaffolder to use IDbContextFactory instead of injecting the DbContext directly in to components

[danroth27]

We've received feedback from users that the component code generated by the Blazor CRUD scaffolder should use the IDbContextFactory instead of injecting the DbContext directly to avoid making multiple overlapping queries with the same DbContext instance. With static server-side rendering this is less likely to happen, but we think it's best to make the change to be in line with our documented Blazor guidance.