Update outdated java span profile information

[simonswine]

I had been going through those docs with one of our customers, I think the code blocks are very confusing and I think settings should be set using environment variables.

I do hope I did not misunderstand anything.

[github-actions]

This PR must be merged before a backport PR will be created.

[knylander-grafana]

One small question, but otherwise, looks good. Thank you for updating the docs!

[github-actions]

The backport to release/v1.6 failed:

Validation Failed: "Could not resolve to a node with the global id of 'T_kwDOAG3Mbc4AczmP'."

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-3339-to-release/v1.6 origin/release/v1.6
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x fa05d6bd59c1db5b09ae5e211723ad7d2fb09b70

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-3339-to-release/v1.6
# Create the PR body template
PR_BODY=$(gh pr view 3339 --json body --template 'Backport fa05d6bd59c1db5b09ae5e211723ad7d2fb09b70 from #3339{{ "\n\n---\n\n" }}{{ index . "body" }}')
# Create the PR on GitHub
echo "${PR_BODY}" | gh pr create --title '[release/v1.6] Update outdated java span profile information' --body-file - --label 'type/docs' --label 'backport' --base release/v1.6 --milestone release/v1.6 --web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-3339-to-release/v1.6

# Create a pull request where the `base` branch is `release/v1.6` and the `compare`/`head` branch is `backport-3339-to-release/v1.6`.

# Remove the local backport branch
git switch main
git branch -D backport-3339-to-release/v1.6