[ERM-71] Rollout manager: status notifications overlap each other

[MarinaVN]

Describe the bug
When multiple rollout processes are started, the user should receive completion notifications displayed at the top of the page.

To Reproduce
Steps to reproduce the behavior:

1. Srart several rollout process one by one (choose big folders to reproduce the bag)
2. Whait for the end of the rollout procees.
3. Pay attention to the top of the page
4. Observe

Actual result: status notifications overlap each other

Expected behavior
All the notifications should be rendered seperatly, without overlapping.

Screenshots