querier: default to using batch.NewChunkMergeIterator

[dimitarvdimitrov]

This is a follow-up of #6673

[pracucci]

Nice job, LGTM!

[grafanabot]

The backport to r266 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 branch
git switch --create backport-6814-to-r266 origin/r266
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x e09acc913ef3cd9cdf303728ac6c3b7ff3272ac3
# Push it to GitHub
git push --set-upstream origin backport-6814-to-r266
git switch main
# Remove the local backport branch
git branch -D backport-6814-to-r266

Then, create a pull request where the base branch is r266 and the compare/head branch is backport-6814-to-r266.

[grafanabot]

The backport to r267 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 branch
git switch --create backport-6814-to-r267 origin/r267
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x e09acc913ef3cd9cdf303728ac6c3b7ff3272ac3
# Push it to GitHub
git push --set-upstream origin backport-6814-to-r267
git switch main
# Remove the local backport branch
git branch -D backport-6814-to-r267

Then, create a pull request where the base branch is r267 and the compare/head branch is backport-6814-to-r267.