NotePermissions: Remove default constructors

As discussed in #835 we don't want to have default constructors and prefer .create methods.
Because the created NoteGroupPermission and NoteUserPermission are not saved to the DB by themselves, but are saved via a change to the Note using a Pick<Class, attributes>-style return type is not helpful here as every single time the .create functions are called a full object is required.
The mock calls in the PermissionService test are not needed and break the .create calls so they got removed.

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/permissions/note-group-permission.entity.ts

@@ -18,4 +18,14 @@ export class NoteGroupPermission {
 
   @Column()
   canEdit: boolean;
+
+  // eslint-disable-next-line @typescript-eslint/no-empty-function
+  private constructor() {}
+
+  public static create(group: Group, canEdit: boolean): NoteGroupPermission {
+    const groupPermission = new NoteGroupPermission();
+    groupPermission.group = group;
+    groupPermission.canEdit = canEdit;
+    return groupPermission;
+  }
 }