docs: correct directory walk error guidance

Describe the merged #22956 behavior: log and skip non-ENOENT walker errors, continue traversal, and retain ENOENT rejection. Clarify that completion does not guarantee every entry was visited.

Addresses review r4267074238. Verified against appium4 implementation and checked the documentation diff.

packages/appium/docs/en/guides/migrating-3-to-4.md

@@ -491,8 +491,8 @@ The following `@appium/support` exports have been removed: `process` (`getProces
   ([#22880](https://github.com/appium/appium/pull/22880),
   [#22954](https://github.com/appium/appium/pull/22954),
   [#22958](https://github.com/appium/appium/pull/22958)).
-* `fs.walkDir()` now rejects on all walker errors, such as `EACCES` and `ELOOP`, instead of leaving
-  the returned promise pending for errors other than `ENOENT`
+* `fs.walkDir()` now continues after walker errors such as `EACCES` and `ELOOP` instead of hanging.
+  These errors are logged and affected entries skipped; `ENOENT` still rejects the returned promise
   ([#22956](https://github.com/appium/appium/pull/22956)).
 * Both `ipc.unsubscribe(topic, subscriber)` and `subscription.unsubscribe()` now finish waiting
   async iterators and notify observers once. An observer that throws still propagates its error
@@ -502,7 +502,8 @@ The following `@appium/support` exports have been removed: `process` (`getProces
 !!! info "Actions Needed"
 
     If you intend to move a symlink's target, resolve it explicitly before calling `fs.mv()`.
-    Handle directory-walk rejections and allow IPC consumers to finish when unsubscribed
+    A completed directory walk may have skipped entries; check warnings if completeness matters.
+    Allow IPC consumers to finish when unsubscribed
 
 ### Legacy Test Pages Removed From `@appium/base-driver`