mod_commands: fix nullptr crash in uuid_record when argc=4

[jack3z]

Description

This PR fixes a null pointer crash in mod_commands.c when executing the uuid_record API command.

The bug was caused by an incorrect argument count check:

• Original code used if (argc > 3) and accessed argv[4] directly
• When argc == 4, argv[4] is NULL, passing a null pointer to switch_url_decode()
• This leads to an immediate crash in switch_url_decode at src/switch_utils.c:3540

Fix: Changed the condition from argc > 3 to argc > 4 to ensure argv[4] is valid before accessing it.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Code cleanup / refactor

Related Issues

No existing issue reported; this bug was discovered via production crash stack trace.

Testing

• Added/updated unit tests
• Tested manually
• Tested with live SignalWire credentials (if applicable)

Manual testing verification:

1. Test uuid_record with 4 arguments (argc=4) → No crash, works safely
2. Test uuid_record with 5 arguments (argc=5) → Functions as expected
3. Verified the original crash scenario no longer occurs

Checklist

• I have read the CONTRIBUTING guidelines
• My code follows the project's style guidelines
• I have added tests for my changes (if applicable)
• I have updated documentation (if applicable)
• All existing tests pass

Additional Notes

Crash stack trace:

[jack3z]

Additional Notes

Crash stack trace:
#0 0x00007f334319da2f in switch_url_decode (s=0x0) at src/switch_utils.c:3540
#1 0x00007f33333ea0ec in session_record_function at mod_commands.c:4710

This is a critical stability fix for production environments using uuid_record.