Cody: Fix auto scrolling

[umpox]

Description

• Fixes auto scroll
• Ensures that any new transcript still scrolls to the bottom (e.g. when navigating between history)

related: #53641

Test plan

[toolmantim]

fyi I've been working to resolve the design for the scroll/follow button (and stop generating, and feedback) here: https://www.figma.com/proto/9112BsKsJc1BpO2j8XYwLL/%F0%9F%A4%96-Cody-VS-Code-%5BMain%5D?page-id=3250%3A136841&type=design&node-id=3532-142502&viewport=-7791%2C-3472%2C1&scaling=min-zoom&starting-point-node-id=3532%3A142502&mode=design (doesn't have a web equivalent yet). Not sure if it directly relates to this.

[sqs]

semi-automated message Cody's source code has moved to a new repository, https://github.com/sourcegraph/cody.

I've migrated this branch for you: https://github.com/sourcegraph/cody/compare/tr/cody-scroll-fix?expand=1. If you still intend to merge this change, please reopen your PR on that new repository.

Script that I used to migrate that branch

#!/bin/bash

# run like `move-branch.sh branch-name` within a separate clone of sourcegraph/sourcegraph

set -eux

BRANCH=$1

git fetch origin refs/heads/$BRANCH:refs/remotes/origin/$BRANCH
git filter-repo \
	--force \
	--refs refs/remotes/origin/$BRANCH \
	--path client/cody \
	--path 'client/cody-icons-font' \
	--path 'client/cody-shared' \
	--path 'client/cody-ui' \
	--path 'client/cody-web' \
	--path 'client/cody-agent' \
	--path 'client/cody-slack' \
	--path 'client/cody-cli' \
	--path-rename client/: \
	--path-rename cody/:vscode/ \
	--path-rename cody-web/:web/ \
	--path-rename cody-agent/:agent/ \
	--path-rename cody-slack/:slack/ \
	--path-rename cody-cli/:cli/ \
	--path-rename cody-icons-font/:lib/icons/ \
	--path-rename cody-shared/:lib/shared/ \
	--path-rename cody-ui/:lib/ui/ \
	--message-callback 'import re;return re.sub(br"(?<!\[)#(\d{4,5})", br"https://github.com/sourcegraph/sourcegraph/pull/\1", message)'

git filter-repo --invert-paths --use-base-name --path-glob '*.bazel' --path 'CODENOTIFY'

git push https://github.com/sourcegraph/cody refs/heads/$BRANCH:$BRANCH

In case it's helpful, here are some of the path mappings from the old repository (https://github.com/sourcegraph/sourcegraph) to the new repository (https://github.com/sourcegraph/cody):

• client/cody/ -> vscode/
• client/cody-shared/ -> lib/shared/
• client/cody-ui/ -> lib/ui/

Thank you for the PR, and sorry for the inconvenience!