Reverting an override redirects the user to an edit form for a new override and therefore still sets the new override as "unsaved changes", which is confusing

Postponed on #2988970: Layout Builder should make it easier to modify the default layout for an entity type when viewing an entity

This doesn't need to be postponed on that issue, now that we know the scope of the solution there.
Updated the issue summary

Also, I should note that there was one other concern about reverting: currently in HEAD if you remove all of the sections from an override, it's the same as reverting. And this is very confusing!
But, that's being fixed in #3030647: Do not add a section when editing an empty layout, or differentiate between new layouts and existing empty layouts which is RTBC.

I meant to mention: I filled in the issue summary based on both the historical comment from @EclipseGc as well as a conversation today.
Also, I am re-updating the issue summary based on discussion with @DyanneNova where she expressed interest for the redirect fix solution.

1. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
   @@ -251,12 +251,13 @@ public function testLayoutBuilderUi() {
   +    $assert_session->addressEquals('node/1');
   

   Just one additional check to ensure we're in the right place after reverting.

2. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
   @@ -251,12 +251,13 @@ public function testLayoutBuilderUi() {
   -    $assert_session->pageTextContains('Placeholder for the "Extra label" field');
   +    $assert_session->pageTextContains('Extra, Extra read all about it.');
   

   These two strings are asserted multiple times throughout the test. One is used when viewing the Layout Builder UI and one is when viewing the actual result. Because of the changed redirect after reverting, this switches the expectation.

Tagging for usability review