Api v2 update task

[c8y3]

This PR add endpoint PUT /api/v2/cases/{case_identifier}/tasks/{identifier} to update a case. Here are the things changed in this PR:

• added endpoint PUT /api/v2/cases/{case_identifier}/tasks/{identifier} in app.blueprints.rest.v2.cases.tasks
• tests: added associated tests
• deprecated endpoint POST /case/tasks/update/int:cur_id
• simplification: have method tasks_update expect a CaseTasks object instead of an identifier in app.business.tasks (the get_task is done before)
• simplification: app.blueprints.pages.case.case_tasks_routes.py extracted method get_task_assignees from method get_task_with_assignees, removed the more complicated method get_task_with_assignees
• quality: split ruff check in its own job, so that we get the result faster
• quality: removed all unused imports
• quality: removed indirect imports in app.models.init
• quality: activated rule F401 (unused imports)
• quality: replaced case_id by case_identifier in app.blueprints.rest.v2.cases.iocs
• quality: using string interpolation rather than string concatenation in ui/src/pages/case.tasks.js