fix(ui): incorrect error states (#11574)

Fixes https://github.com/payloadcms/payload/issues/11568

### What? Out of sync errors states
- Collaspibles & Tabs were not reporting accurate child error counts
- Arrays could get into a state where they would not update their error
states
- Slight issue with toasts 

### Tabs & Collapsibles
The logic for determining matching field paths was not functioning as
intended. Fields were attempting to match with paths such as `_index-0`
which will not work.

### Arrays
The form state was not updating when the server sent back errorPaths.
This PR adds `errorPaths` to `serverPropsToAccept`.

### Toasts
Some toasts could report errors in the form of `my > > error`. This
ensures they will be `my > error`

### Misc
Removes 2 files that were not in use:
- `getFieldStateFromPaths.ts`
- `getNestedFieldState.ts`

test/helpers/assertToastErrors.ts

@@ -0,0 +1,27 @@
+import type { Page } from '@playwright/test'
+
+import { expect } from '@playwright/test'
+
+export async function assertToastErrors({
+  page,
+  errors,
+}: {
+  errors: string[]
+  page: Page
+}): Promise<void> {
+  const message =
+    errors.length === 1
+      ? 'The following field is invalid:'
+      : `The following fields are invalid (${errors.length}):`
+  await expect(
+    page.locator('.payload-toast-container li').filter({ hasText: message }),
+  ).toBeVisible()
+  for (let i = 0; i < errors.length; i++) {
+    const error = errors[i]
+    if (error) {
+      await expect(
+        page.locator('.payload-toast-container [data-testid="field-errors"] li').nth(i),
+      ).toHaveText(error)
+    }
+  }
+}