[a11y] Restore logic for container title

The change to disable supplemental descriptions
(https://chromium-review.googlesource.com/c/chromium/src/+/6622929)
unintentionally broke the logic for setting the
`containerTitle`. This caused `containerTitle`
content to be incorrectly populated into the
`text` property of `AccessibilityNodeInfo` instead.

The `text` property is meant for on-screen visible
text, whereas `containerTitle` is for non-visual
descriptions for assistive technologies.

This change restores the `containerTitle` behavior
to what it was before the supplemental description
feature was implemented
(https://chromium-review.googlesource.com/c/chromium/src/+/6411876),
ensuring this distinction is respected.

Manual verification was performed:
* Test diffs confirm the accessible name correctly
  moved from the `text` property back to
  `containerTitle`.
* A diff against the codebase state before the
  regression confirmed `containerTitle` values are
  correct.
* New `text` values in the diffs are correctly
  populated based on visual content rules, as
  described in
  go/a11y-visual-content-and-accessible-names.


Change-Id: I5f1e5a305cd5e700edb837847328dd24640b5614
Bug: 413737580
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6820248
Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Lucas Radaelli <lucasradaelli@google.com>
Cr-Commit-Position: refs/heads/main@{#1497330}