Small improvement: Repository directory check before updating submodules

[luizferrbarbosa]

Description:

This pull request introduces a small but significant improvement to the build script. It implements a directory check before executing the command to update submodules within the repository.

Changes Made:

• Added a conditional check to verify the existence of content within the repository directory before running the 'git submodule update --init --recursive' command.
• Removed an unused variable to streamline the verification process.

Why this Change?

Previously, the script would unconditionally attempt to update submodules, even if the repository directory was empty. This improvement ensures that the submodule update command is only executed when there's content present, optimizing the process and avoiding unnecessary executions.

Benefits:

• Enhances the efficiency of the update process by preventing unnecessary commands.
• Improves script robustness by checking the repository directory directly.

How to Verify:

1. Run the build script.
2. Observe that the submodule update command is triggered only if there's content in the repository directory.
3. Confirm that the build process functions as expected. This change aims to streamline the build process and contribute to the overall efficiency of the repository.

[clickot]

@luizferrbarbosa as far as i can see your PR does not change any behavior but simply replaces the hardcoded "ungoogled-chromium" subdir with the GIT_REPO var. I'll merge it nontheless. Thank you.

[luizferrbarbosa]

Thank you for reviewing and merging my Pull Request!