fix(nextjs): Use indexing to iterate in for-loops in vercel script

[lobsterkatie]

It turns out that bash and zsh handle for-loops differently. Consider the following code:

animals=("aardvark" "baboon" "coati")

echo -e "\nno indexing:"
for animal in $animals; do
  echo $animal
done

echo -e "\nwith indexing:"
for animal in ${animals[@]}; do
  echo $animal
done

In zsh, you get two copies of the full list:

> source indexing-test.sh

no indexing:
aardvark
baboon
coati

with indexing:
aardvark
baboon
coati

In bash, however, if you don't index, you only get the first element:

> source indexing-test.sh 

no indexing:
aardvark

with indexing:
aardvark
baboon
coati

Since the install-sentry-from-branch.sh script runs under bash (on vercel), we need to index in order for our for-loops to work.

[github-actions]

size-limit report

Path	Size
@sentry/browser - CDN Bundle (gzipped)	21.46 KB (0%)
@sentry/browser - Webpack	22.47 KB (0%)
@sentry/react - Webpack	22.5 KB (0%)
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	28.97 KB (-0.01% 🔽)