Update dependency-injection-usage.md

[fcdeveloper00]

Hi, thank you very much for providing us these great articles. They're very helpful. 👍🙂

There are two typo issues in Register services for DI section (exactly the last part of it which starts with "The app: " )
that are addressed:

• The first line states that the app creates an IHostBuilder, but Host.CreateApplicationBuilder()
  returns an IHostApplicationBuilder.

• In the last line, the ExemplifyScoping method's name changed to ExemplifyServiceLifetime.

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