Version 6.0.1+ ignores --silent flag

I've created a reproduction of this bug here: https://github.com/apellerano-pw/htmlbars-silent-repro

**Steps to reproduce**
1. have an ember app with some kind of deprecation output, e.g. use `{{#with}}` in Ember 3.28
2. use ember-cli-htmlbars 6.0.1 or higher
3. run `ember test --silent` (in the repro repo you can do `npm run repro`)

**Expected**

There is no build output, only test output

**Actual**

Deprecation output will be shown in addition to test output

**Workaround**

Pin your version of ember-cli-htmlbars to 6.0.0

Start with the linked htmlbars-silent-repro repository and run npm run repro to confirm the regression with ember-cli-htmlbars 6.0.1 or higher, then compare it with 6.0.0. Trace how ember test --silent reaches build and deprecation output. Done means the reproduction produces only test output while using the newer version.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.