Fix misc issues found with java-client+recordings

[swallez]

Fixes #1887

[sethmlarson]

Looks great, few thoughts:

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
enrich.delete_policy	🟢	5/5	5/5
enrich.execute_policy	🟢	6/6	6/6
enrich.get_policy	🟢	6/6	6/6
enrich.put_policy	🟢	6/6	6/6
enrich.stats	🟢	5/5	5/5
ingest.simulate	🟢	4/4	4/4
license.post	🟢	1/1	1/1
ssl.certificates	🟢	2/2	2/2
transform.delete_transform	🟢	9/9	9/9
transform.get_transform_stats	🟢	31/31	31/31
transform.get_transform	🟢	26/26	26/26
transform.preview_transform	🟢	17/17	17/17
transform.put_transform	🟢	26/26	26/26
transform.reset_transform	🟢	4/4	4/4
transform.start_transform	🟢	26/26	26/26
transform.stop_transform	🟢	15/15	15/15
transform.update_transform	🟢	13/13	13/13
transform.upgrade_transforms	🟢	2/2	2/2
xpack.usage	🔴	19/19	0/15

You can validate these APIs yourself by using the make validate target.

[sethmlarson]

LGTM

[github-actions]

The backport to 7.17 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-7.17 7.17
# Navigate to the new working tree
cd .worktrees/backport-7.17
# Create a new branch
git switch --create backport-1945-to-7.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick --mainline 1 b0f41a5f37ace44ee7476838f433b3128caef79e
# Push it to GitHub
git push --set-upstream origin backport-1945-to-7.17
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-7.17

Then, create a pull request where the base branch is 7.17 and the compare/head branch is backport-1945-to-7.17.