fix: test case ut_lind_fs_open_empty_directory

[ChinmayShringi]

Description

Fixes # (issue)

This PR addresses the issue where an empty string "" passed as a file path was incorrectly classified as a directory, returning EISDIR (Is a directory). The changes ensure that the correct error (ENOENT - No such file or directory) is returned when an empty path is provided.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• The fix has been tested by running the specific test case: cargo test ut_lind_fs_open_empty_directory, which verifies that providing an empty path correctly results in ENOENT and not EISDIR.

Checklist

• My code follows the style guidelines of this project.
• I have thoroughly commented my code, especially in hard-to-understand areas.
• I have performed a self-review of my code and fixed all errors and warnings.
• I have added appropriate tests for the functionality or bug fix.
• My changes do not introduce any new warnings.
• Dependent changes have been added to the pull request or merged (native-client, lind-glibc, lind-project).
• Documentation has been updated (if applicable).

[Yaxuan-w]

LGTM