Navigation Editor - theme location change causes rerender

[grzim]

Description

Mentioned in #29458
When a user changes the value in any of the theme location dropdowns in Navigation Editor the entire editor rerenders.

Step-by-step reproduction instructions

Expected behaviour

New menu is applied to the location and the window remains open

Actual behaviour

The entire editor rerenders

Code snippet (optional)

Could be related to useNavigationEditor:
https://github.com/WordPress/gutenberg/blob/trunk/packages/edit-navigation/src/components/layout/index.js#L59
That the navigationPost used is temporarily unavailable, which makes the editor briefly not rendered:
https://github.com/WordPress/gutenberg/blob/trunk/packages/edit-navigation/src/components/layout/index.js#L68

WordPress information

• Gutenberg version: 10.2.1

Device information

• Device: MacOS
• Operating system: Big Sur
• Browser: Chrome 89

[grzim]

closed with #30340