[MINOR] Add artifacts to .gitignore

### What changes were proposed in this pull request?
Add `artifacts` to `.gitignore`

### Why are the changes needed?
```
bin/spark-shell --remote "local[*]"
```

generates a lot of files in it
```
(spark_dev_312) ➜  spark git:(master) ✗ git status
On branch master
Your branch is ahead of 'origin/master' by 1386 commits.
  (use "git push" to publish your local commits)

Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd0$.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd0$Helper.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd0.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd1$.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd1$Helper.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd1.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd2$.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd2$Helper.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd2.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd9999999$.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/85157252-6f8a-46b3-ab42-585c70184d08/classes/ammonite/$sess/cmd9999999$Helper.class
	new file:   artifacts/spark-37fc351b-0207-4957-ac39-5b23ae672c0c/8515
```

### Does this PR introduce _any_ user-facing change?
No, dev only

### How was this patch tested?
manually check

### Was this patch authored or co-authored using generative AI tooling?
No

Closes #47936 from zhengruifeng/infra_artifacts.

Authored-by: Ruifeng Zheng <[email protected]>
Signed-off-by: Kent Yao <[email protected]>

.gitignore

@@ -26,6 +26,7 @@
 .scala_dependencies
 .settings
 .vscode
+artifacts/
 /lib/
 R-unit-tests.log
 R/unit-tests.out