Revert "Reland "[Tab Groups] Updated Shrink Animation for Final Incognito Tab""

This reverts commit 8b7cde1e4ff01bb20d05d52b36fe2f3e8c31c989.

Reason for revert: crbug.com/396046588

Original change's description:
> Reland "[Tab Groups] Updated Shrink Animation for Final Incognito Tab"
>
> This reverts commit 7284c0e088f223c4e4069f7e632e26be783916b0.
>
> - null checks added
>
> Reason for revert: bug fixed.
>
> Original change's description:
> > Revert "[Tab Groups] Updated Shrink Animation for Final Incognito Tab"
> >
> > This reverts commit 052ba202b4571dc037e47dd4230a46a7dde4afd4.
> >
> > Reason for revert: bug blocks major release.
> >
> > Original change's description:
> > > [Tab Groups] Updated Shrink Animation for Final Incognito Tab
> > >
> > > - Ensures the final shrink animation for the incognito tab switcher
> > >         runs when closing the tab switcher
> > > - Track animation completion using a Supplier
> > > - Clean up method is aware of whether the final tab is closed via
> > >         swipe
> > > - Clean up method is aware of whether the final tab is closed via
> > >         tab grid dialog
> > > - Animation Recording: https://drive.google.com/file/d/1G-bdbIcQI9wY6HQ_Kx3KuUrfsN9GIz4S/view?usp=sharing&resourcekey=0-RLXdKuJIVe57phjl-binLQ
> > >
> > > Bug: 362329064
> > > Change-Id: Iac81cbc04cc585debdade24c9b090b13e08bf123
> > > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6184553
> > > Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
> > > Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
> > > Reviewed-by: Sky Malice <skym@chromium.org>
> > > Commit-Queue: Fiaz Muhammad <mfiaz@google.com>
> > > Cr-Commit-Position: refs/heads/main@{#1414236}
> >
> > Bug: 393786206
> > Change-Id: I2dea373a751f70e3ede432ef480a48a658b5796b
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6225860
> > Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
> > Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> > Commit-Queue: Fiaz Muhammad <mfiaz@google.com>
> > Cr-Commit-Position: refs/heads/main@{#1414919}
>
> Bug: 393786206
> Change-Id: Id72be59b0eae0e503b20c7a7d34f96b5ea77dc83
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6242837
> Commit-Queue: Fiaz Muhammad <mfiaz@google.com>
> Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1418176}

Bug: 393786206, 396046588
Change-Id: I89e0e848aadc03852e4dc72e08f96d047de1c1d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6258675
Reviewed-by: Sky Malice <skym@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Calder Kitagawa <ckitagawa@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1419399}