refactor: entity not found exceptions handler

repositories/project.py

@@ -10,6 +10,7 @@ class ProjectRepository(
     RepCrudMixin[Project, CreateProjectSchema, UpdateProjectSchema]
 ):
     entity_class = Project
+    entity_not_found_msg = "Проект не найден"
 
     def _process_get_all_stmt(self, stmt: Select) -> Select:
         return stmt.order_by(Project.id)