refactor!: Remove unused `is_certificate_valid` function

[MICROBA-1354]

* Remove unused `is_certificate_valid` function

openedx/core/djangoapps/certificates/api.py

@@ -30,13 +30,6 @@ def _enabled_and_instructor_paced(course):
     return False
 
 
-def is_certificate_valid(certificate):
-    """
-    Returns True if the student has a valid, verified certificate for this course, False otherwise.
-    """
-    return CourseEnrollment.is_enrolled_as_verified(certificate.user, certificate.course_id) and certificate.is_valid()
-
-
 def can_show_certificate_message(course, student, course_grade, certificates_enabled_for_course):
     """
     Returns True if a course certificate message can be shown

openedx/core/djangoapps/certificates/tests/test_api.py

@@ -10,7 +10,6 @@ from django.test import TestCase
 from edx_toggles.toggles import LegacyWaffleSwitch
 from edx_toggles.toggles.testutils import override_waffle_switch
 
-from common.djangoapps.course_modes.models import CourseMode
 from common.djangoapps.student.tests.factories import CourseEnrollmentFactory, UserFactory
 from openedx.core.djangoapps.certificates import api
 from openedx.core.djangoapps.certificates.config import waffle as certs_waffle
@@ -119,36 +118,6 @@ class CertificatesApiTestCase(TestCase):
         with configure_waffle_namespace(feature_enabled):
             assert expected_value == api.can_show_certificate_available_date_field(self.course)
 
-    @ddt.data(
-        (CourseMode.VERIFIED, CertificateStatuses.downloadable, True),
-        (CourseMode.VERIFIED, CertificateStatuses.notpassing, False),
-        (CourseMode.AUDIT, CertificateStatuses.downloadable, False)
-    )
-    @ddt.unpack
-    def test_is_certificate_valid(self, enrollment_mode, certificate_status, expected_value):
-        self.enrollment.mode = enrollment_mode
-        self.enrollment.save()
-
-        self.certificate.mode = CourseMode.VERIFIED
-        self.certificate.status = certificate_status
-
-        assert expected_value == api.is_certificate_valid(self.certificate)
-
-    @ddt.data(
-        (CourseMode.VERIFIED, CertificateStatuses.downloadable, True),
-        (CourseMode.VERIFIED, CertificateStatuses.notpassing, False),
-        (CourseMode.AUDIT, CertificateStatuses.downloadable, False)
-    )
-    @ddt.unpack
-    def test_available_date(self, enrollment_mode, certificate_status, expected_value):
-        self.enrollment.mode = enrollment_mode
-        self.enrollment.save()
-
-        self.certificate.mode = CourseMode.VERIFIED
-        self.certificate.status = certificate_status
-
-        assert expected_value == api.is_certificate_valid(self.certificate)
-
     @ddt.data(
         (True, True, False),  # feature enabled and self-paced should return False
         (True, False, True),  # feature enabled and instructor-paced should return True