There's code injection vulnerability of alluxio.util.CommonUtils.getUnixGroups

[LetianYuan]

Affected Alluxio Version:
All the version before the latest(2.9.3).

Describe the vulnerability
Passing username with special characters of unix shell as parameter of alluxio.util.CommonUtils.getUnixGroups(java.lang.String) can inject malicious commands. For example, the following code
CommonUtils.getUnixGroups("| echo 123");
would finally execute bash -c id -gn | echo 123; id -Gn. Therefore malicious code echo 123 is executed.

To Reproduce
Just execute alluxio.util.CommonUtils.getUnixGroups("| echo 123") would reproduce it.

Are you planning to fix it
I've already submitted a pull request. See #17256.

[ChunxuTang]

@LetianYuan Thanks for raising the issue and submitting the PR!
FYI: @yyongycy