Revert "holding space: Change Tote previews default value"

This reverts commit 330db8b5.

Reason for revert: Might be related to 
ImeMenuTrayTest.ShowingEmojiKeysetHidesBubble failure on multiple bots.

Original change's description:
> holding space: Change Tote previews default value
>
> This is based on the kHoldingSpacePredictability experiment flag
>
> Bug: 1354520
> Change-Id: Ie1dbf26e488ca26bb7b00edd28518f50237f4d53
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3841852


> Reviewed-by: David Black <dmblack@google.com>
> Auto-Submit: Sam Cackett <samcackett@google.com>
> Commit-Queue: Sam Cackett <samcackett@google.com>
> Cr-Commit-Position: refs/heads/main@{#1039177}

Bug: 1354520, 1356543
Change-Id: Ib94fac11bb4621163ffd23791a06ac4006d442be
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3857202
Owners-Override: Owen Min <zmin@chromium.org>
Commit-Queue: Owen Min <zmin@chromium.org>
Auto-Submit: Owen Min <zmin@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1039263}