Separator: The effect of colour is only visible when we lost the focus from the Separator block to other block

[kmadhak]

Describe the bug
In Separator when we change the colour then it only affect the middle of the separator but when we lost the focus from Separator to other block then the colour effect is visible in whole Separator block

To reproduce
Steps to reproduce the behavior:

1. Go to 'Editor'
2. Add new page
3. Click on 'add block'
4. Select the block 'Separator'
5. Select the style 'Default / Wide Line'
6. Set the colour 'brown/silver'
7. See error

Expected behavior
The effect of colour should be in whole block instantly not after the lost focus

Screenshots
https://prnt.sc/tvncud
https://prnt.sc/tvncud

Video
for more detail please view the attached video
https://www.loom.com/share/3197ab90d1cd4468a1cbd37f117aa5b1

Editor version (please complete the following information):

• WordPress version: 5.5-beta1
• default

Desktop (please complete the following information):

• OS: Windows
• Browser chrome
• Version 84.0.4147.105 (Official Build) (64-bit)

[aristath]

I just tested this with the master branch and can't replicate the issue, it was fixed in #24366

The change didn't make it in WP5.5 so it should be included in the next update 👍