Fix browser entrypoint

[t3chguy]

Fixes #3013

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Here's what your changelog entry will look like:

🐛 Bug Fixes

• Fix browser entrypoint (#3051). Fixes Failed to resolve entry for package "matrix-js-sdk" #3013.

[RiotRobot]

The backport to staging failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-staging staging
# Navigate to the new working tree
cd .worktrees/backport-staging
# Create a new branch
git switch --create backport-3051-to-staging
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 d7bf0f85c0f26b9b273dec5b6dbc2465eeb0e0eb
# Push it to GitHub
git push --set-upstream origin backport-3051-to-staging
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-staging

Then, create a pull request where the base branch is staging and the compare/head branch is backport-3051-to-staging.