chore: Remove deprecated argument for signal

Part-of: <https://dev.funkwhale.audio/funkwhale/funkwhale/-/merge_requests/2709>

api/funkwhale_api/common/signals.py

@@ -1,6 +1,6 @@
 import django.dispatch
 
-mutation_created = django.dispatch.Signal(providing_args=["mutation"])
-mutation_updated = django.dispatch.Signal(
-    providing_args=["mutation", "old_is_approved", "new_is_approved"]
-)
+""" Required args: mutation """
+mutation_created = django.dispatch.Signal()
+""" Required args: mutation, old_is_approved, new_is_approved """
+mutation_updated = django.dispatch.Signal()

api/funkwhale_api/moderation/signals.py

@@ -1,3 +1,4 @@
 import django.dispatch
 
-report_created = django.dispatch.Signal(providing_args=["report"])
+""" Required argument: report """
+report_created = django.dispatch.Signal()

api/funkwhale_api/music/signals.py

@@ -1,5 +1,4 @@
 import django.dispatch
 
-upload_import_status_updated = django.dispatch.Signal(
-    providing_args=["old_status", "new_status", "upload"]
-)
+""" Required args: old_status, new_status, upload """
+upload_import_status_updated = django.dispatch.Signal()