[BUU] Variant updates ignored when error on bulk updating products

[dacook]

Description

Raised in #11750:

When product and associated variant are updated, but there are errors:
Neither should be saved, summary should show, and unsaved values retained with red/orange border.
But these fail due to #11748

1. product has error, variant has error. 🆇 Variant values are lost
2. product has error, variant has valid changes. 🆇 Variant values are lost
3. product has valid changes, variant has error. 🆇 Product changes got saved, but shouldn't have been until variant error was resolved
   

Expected Behavior

Actual Behaviour

Steps to Reproduce

Animated Gif/Screenshot

Workaround

Severity

Your Environment

• Version used:
• Browser name and version:
• Operating System and version (desktop or mobile):

Possible Fix

See #11748