Fix optional Processor fields and add missing fields

[swallez]

Fixes the optionality of ingest processor fields (most of them are optional) and add a few missing ones.

Checked with the docs.

[github-actions]

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

API	Status	Request	Response
ingest.delete_pipeline	🟢	11/11	11/11
ingest.geo_ip_stats	⚪	Missing test	Missing test
ingest.get_pipeline	🟢	22/22	22/22
ingest.processor_grok	🟢	1/1	1/1
ingest.put_pipeline	🟢	30/30	30/30
ingest.simulate	🟢	4/4	4/4

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

[Anaethelion]

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-1970-to-7.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick --mainline 1 b3bfcd6161ba225eca397d972d1ca8342a24cfb3
# Push it to GitHub
git push --set-upstream origin backport-1970-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-1970-to-7.17.