fix: canvas autoscroll issue when selecting instances (#4174)

## Description

closes #4169

## Steps for reproduction

Shoud be tested well as having various scroll/resize/mutation obserevers
we have, everything can cause infinite cycle

## Code Review

- [ ] hi @kof, I need you to do
  - conceptual review (architecture, feature-correctness)
  - detailed review (read every line)
  - test it on preview

## Before requesting a review

- [ ] made a self-review
- [ ] added inline comments where things may be not obvious (the "why",
not "what")

## Before merging

- [ ] tested locally and on preview environment (preview dev login:
5de6)
- [ ] updated [test
cases](https://github.com/webstudio-is/webstudio/blob/main/apps/builder/docs/test-cases.md)
document
- [ ] added tests
- [ ] if any new env variables are added, added them to `.env` file

Author: istarkov

apps/builder/app/canvas/collapsed.ts

@@ -179,6 +179,12 @@ const recalculate = () => {
     }
   }
 
+  // If most elements are collapsed at the next step, scrollHeight becomes equal to clientHeight,
+  // which resets the scroll position. To prevent this, we set the document's height to the current scrollHeight
+  // to preserve the scroll position.
+  const preserveHeight = document.documentElement.style.height;
+  document.documentElement.style.height = `${document.documentElement.scrollHeight}px`;
+
   // Now combine all operations in batches.
 
   // 1. Remove all collapsed attributes
@@ -222,6 +228,8 @@ const recalculate = () => {
   for (const [element, value] of collapsedElements.entries()) {
     element.setAttribute(collapsedAttribute, value);
   }
+
+  document.documentElement.style.height = preserveHeight;
 };
 
 /**