Removing time estimates during edit dosen't update the project/task

[XotEmBotZ]

Description

When the time estimate from task/project is removed and then saved the time estimate is not removed. Instead when it is replaced with zero and saved it is removed.

Steps To Reproduce

1. Create a project/task
2. Edit the project/task
3. Remove the project/task
4. Save the project/task

Self-hosted or Cloud?

Self-Hosted

Version of solidtime: (for self-hosted)

v0.8.0

solidtime self-hosting guide: (for self-hosted)

official docker compose guid

[f616]

@Onatcer since you're editing the timeEstimate, could you please take a lookt to #460