llama-mtmd-cli: Sigint rework in mtmd vision example (#13080)
* Sigint rework in mtmd vision example
* Applied suggestions on mtmd-cli PR
* Forgot to invert one of the conditions
* Update examples/llava/mtmd-cli.cpp
* Removed redundant exit check
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Co-authored-by: pl752 <maximpl752@gmail.com>
Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>