Add warning logs when removing invalid voice commands

[joeljfischer]

Bug Summary

We currently do not notify the developer about invalid voice commands that are automatically removed. We should add those logs.

See Java Suite PR: smartdevicelink/sdl_java_suite#1799

Reproduction Steps

1. Create a voice command without any strings
2. Set voice command

Expected Behavior:
A warning log that the voice command is removed and why is displayed

Observed Behavior:
The voice command is removed with no log for the developer

iOS Version(s)

No response

sdl_ios Version

7.3.2-develop

Testing Environment(s)

n/a - Any

Relevant log output

No response