Fix vulnerability in AssemblyScript SDK install script

[mattjohnsonpint]

Fixes https://github.com/hypermodeinc/modus/security/code-scanning/1

To fix the problem, we should avoid using execSync with a concatenated command string that includes unsanitized environment variables. Instead, we can use execFileSync which accepts command arguments as an array of strings, thus avoiding the risk of command injection.

• Replace the execSync call with execFileSync.
• Construct the command arguments as an array, ensuring that each part of the command is a separate element in the array.
• Import the necessary execFileSync function from the child_process module.