[common][serializers] Replace DRF JSONField with custom version

beat/web/common/serializers.py

@@ -41,6 +41,7 @@ from ..team.models import Team
 from ..common.utils import ensure_html
 from ..common.utils import annotate_full_name
 from ..common.utils import validate_restructuredtext
+from ..common import fields as beat_fields
 
 from .models import Shareable, Versionable, Contribution
 from .exceptions import ContributionCreationError
@@ -301,7 +302,7 @@ class ContributionSerializer(VersionableSerializer):
 
 
 class ContributionModSerializer(serializers.ModelSerializer):
-    declaration = serializers.JSONField(required=False)
+    declaration = beat_fields.JSONField(required=False)
     description = serializers.CharField(required=False, allow_blank=True)
 
     class Meta: