[FIX] project: fixes subtask stage and empty display name

[ropu-odoo]

In this PR fixes following bugs:

• Subtasks don't set by-default to the configured stage. users have to manually set it after saving.
• Expected: stages by default set upon creation.
• the task name goes empty after selecting a project, even if you rewrite it and switch projects. This only happens in the Quick Add feature in the kanban view after enabling timesheets in the project settings.

task-3706741

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:

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[robodoo]

.