\Drupal calls should be avoided in classes, use dependency injection instead

Problem/Motivation

I try to run phpcs coding standard check on the module. I found some dependency injection warning in some files as follows:

FILE: /app/modules/contrib/contacts/src/Form/ContactTabForm.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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49 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: .../modules/contrib/contacts/src/Form/DashboardTabConfigureForm.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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139 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: ...app/modules/contrib/contacts/src/Plugin/Block/ContactsEntity.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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641 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: .../modules/contrib/contacts/src/Controller/DashboardController.php
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FOUND 0 ERRORS AND 3 WARNINGS AFFECTING 3 LINES
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567 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
568 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
612 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: ...es/contrib/contacts/modules/crm_tools/src/Form/OverviewRoles.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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121 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: .../contacts/modules/user_dashboard/src/Routing/RouteSubscriber.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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25 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

FILE: ...trib/contacts/modules/dbs/src/Plugin/Block/DBSStatusAddBlock.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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96 | WARNING | \Drupal calls should be avoided in classes, use
| | dependency injection instead
----------------------------------------------------------------------

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes