[SPARK-33802][INFRA] Override name and email address explicitly when updating PySpark coverage

### What changes were proposed in this pull request?

The current Jenkins job fails as below (https://amplab.cs.berkeley.edu/jenkins/job/spark-master-test-sbt-hadoop-3.2/1726/console)

```
Generating HTML files for PySpark coverage under /home/jenkins/workspace/spark-master-test-sbt-hadoop-3.2/python/test_coverage/htmlcov
/home/jenkins/workspace/spark-master-test-sbt-hadoop-3.2
Cloning into 'pyspark-coverage-site'...

*** Please tell me who you are.

Run

  git config --global user.email "youexample.com"
  git config --global user.name "Your Name"

to set your account's default identity.
Omit --global to set the identity only in this repository.
```

This PR proposes to set both when committing to the coverage site.

### Why are the changes needed?

To make the coverage site keep working.

### Does this PR introduce _any_ user-facing change?

No, dev-only.

### How was this patch tested?

Manually tested in the console but it has to be merged to test in the Jenkins environment.

Closes apache#30796 from HyukjinKwon/SPARK-33802.

Authored-by: HyukjinKwon <[email protected]>
Signed-off-by: HyukjinKwon <[email protected]>

Author: HyukjinKwon

dev/run-tests.py

@@ -521,10 +521,11 @@ def post_python_tests_results():
         # 6. Commit current HTMLs.
         run_cmd([
             "git",
+            "-c user.name='Apache Spark Test Account'",
+            "-c user.email='[email protected]'",
             "commit",
             "-am",
-            "Coverage report at latest commit in Apache Spark",
-            '--author="Apache Spark Test Account <[email protected]>"'])
+            "Coverage report at latest commit in Apache Spark"])
         # 7. Delete the old branch.
         run_cmd(["git", "branch", "-D", "gh-pages"])
         # 8. Rename the temporary branch to master.