Enhance `String.runCommand` to Capture and Emit Real-time Output

[drganjoo]

The String.runCommand function currently lacks the capability to capture and immediately display output lines produced by commands executed in a shell. This enhancement would allow the function to support a parameter enabling the real-time capture and emission of lines as they are generated by the running command.

Implementing this feature would be particularly beneficial for monitoring long-running processes, providing a clearer and more immediate understanding of what is occurring during tests.