Show Actions post step when it's running (#29926) (#29928)

Show Actions post step when it's running (#29926) (#29928)

Backport #29926 by @wolfogre

The post step was always waiting, even if all steps were done. Then,
once the task was done, the post step became success immediately.

Before:

<img width="915" alt="xnip_240320_120228"
src="https://github.com/go-gitea/gitea/assets/9418365/00347430-f998-4c43-917a-bf6dd6d0e333">

After:

<img width="905" alt="xnip_240320_120443"
src="https://github.com/go-gitea/gitea/assets/9418365/a419b111-17c2-4029-a022-c761cc419091">

Co-authored-by: Jason Song <i@wolfogre.com>