Added example script to test Recognizer and Microphone functionality

[Pranavi125]

This PR adds a simple example script (test_sr.py) that demonstrates how to record and recognize speech using the Recognizer and Microphone classes.

✅ Helps new users verify PyAudio installation and microphone setup.
✅ Provides a clear, minimal test for speech recognition functionality.
✅ Addresses issue #628 by adding a working test and setup verification example.

[ftnext]

Hi @Pranavi125, thank you for your interest in contributing to speech_recognition.

I appreciate the effort you put into creating this example script. However, I'm going to close this PR because similar script already exists as examples/microphone_recognition.py