Revert "Create Open Attached Animation for Glic Window widget."

This reverts commit e048fcf27702ac75af743964d1f484f5a39bb117.

Reason for revert: Causes nullptr dereference.

Original change's description:
> Create Open Attached Animation for Glic Window widget.
>
> Updated demo:
> https://drive.google.com/file/d/1fVza4T0ejskxvDeiM4TAHXOjXp0H-gX9/view?usp=sharing&resourcekey=0-UfXM_FU_veDhJkRJloVnwg
>
> This approach runs the animation before we know if the web contents are ready - this gives room for the case that the web contents take too long to load or never load so we can display the error/loading state inside the glic window.
>
> Bug: 385205427
> Change-Id: I7dfb66e7d947c68069857e93ce69fef0e5f2774a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6173926
> Reviewed-by: Ian Wells <iwells@chromium.org>
> Commit-Queue: Sana Akbani <sanaakbani@google.com>
> Cr-Commit-Position: refs/heads/main@{#1407647}

Bug: 385205427
Change-Id: I393630af0917f17e4deaf3cfb07c411e9cb7c85f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6181792
Auto-Submit: Erik Chen <erikchen@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1408033}