Update CMakeLists.txt (IEC-65)

[diplfranzhoepfinger]

esp_modem_config.h is in Folder "include" not in folder private_include

Checklist

• [ ] Component contains License
• [ ] Component contains README.md
• [ ] Component contains idf_component.yml file with url field defined
• [ ] Component was added to upload job
• [ ] Component was added to build job
• [ ] Optional: Component contains unit tests
• [ ] CI passing

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[CLAassistant]

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[tore-espressif]

@diplfranzhoepfinger The current dependency tree is correct. All dependencies are propagated from esp_modem and usb_host_cdc_acm