Consistent use of the string translation trait within classes

The admin forms and the redirect controller are occasionally still using the global t() function:

FILE: openid_connect/src/Controller/RedirectController.php
--------------------------------------------------------------------------
 152 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 162 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 174 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
--------------------------------------------------------------------------

FILE: openid_connect/src/Form/AccountsForm.php
--------------------------------------------------------------------------
 122 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 126 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 151 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 161 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
 182 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
--------------------------------------------------------------------------

FILE: openid_connect/src/Form/SettingsForm.php
--------------------------------------------------------------------------
 202 | WARNING | t() calls should be avoided in classes, use dependency
     |         | injection and $this->t() instead
--------------------------------------------------------------------------

FILE: openid_connect/src/Form/LoginForm.php
--------------------------------------------------------------------------
 80 | WARNING | t() calls should be avoided in classes, use dependency
    |         | injection and $this->t() instead
--------------------------------------------------------------------------

According to Drupal 8 best practices, the string translation trait should be used instead.