InfluxDB: Fix parsing multiple tags on backend mode

[itsmylife]

What is this feature?

This is fixing the response when we have multiple tags in the response. Multiple tags must be separated by a comma in the result. This also allows us to be in sync with the frontend mode result.

Why do we need this feature?

To have a proper output

Who is this feature for?

InfluxDB InfluxQL backend mode users

Special notes for your reviewer:

How to test?

• Run dev environment with feature flag influxdbBackendMigration=true
• Use this query as an example SELECT "usage_idle" FROM "cpu" WHERE $timeFilter GROUP BY "cpu"::tag, "host"::tag
• Observe that you get the response (see it on the legend) back as cpu.usage_idle {cpu: cpu3 host: 41c9dcf3b960}
• Switch to this branch and run the query again
• Observe that you get the response (see it on the legend) back as cpu.usage_idle {cpu: cpu3, host: 41c9dcf3b960}

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.

[grafana-delivery-bot]

The backport to v10.2.x 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-77340-to-v10.2.x origin/v10.2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x 6b13064cf6a5f544f558783cda8d3a2b7bc7f7e7

When the conflicts are resolved, stage and commit the changes:

git add . && git cherry-pick --continue

If you have the GitHub CLI installed:

# Push the branch to GitHub:
git push --set-upstream origin backport-77340-to-v10.2.x
# Create the PR body template
PR_BODY=$(gh pr view 77340 --json body --template 'Backport 6b13064cf6a5f544f558783cda8d3a2b7bc7f7e7 from #77340{{ "\n\n---\n\n" }}{{ index . "body" }}')
# Create the PR on GitHub
echo "${PR_BODY}" | gh pr create --title "[v10.2.x] InfluxDB: Fix parsing multiple tags on backend mode" --body-file - --label "type/bug" --label "datasource/InfluxDB" --label "area/backend" --label "add to changelog" --label "backport" --base v10.2.x --milestone 10.2.x --web

Or, if you don't have the GitHub CLI installed (we recommend you install it!):

# Push the branch to GitHub:
git push --set-upstream origin backport-77340-to-v10.2.x

# Create a pull request where the `base` branch is `v10.2.x` and the `compare`/`head` branch is `backport-77340-to-v10.2.x`.

# Remove the local backport branch
git switch main
git branch -D backport-77340-to-v10.2.x