CVE-2023-6249 ipm: signed to unsigned conversion problem in esp32_ipm_send

[
  {
    "defaultStatus": "unaffected",
    "packageName": "Zephyr",
    "product": "Zephyr",
    "repo": "https://github.com/zephyrproject-rtos/zephyr",
    "vendor": "zephyrproject-rtos",
    "versions": [
      {
        "lessThanOrEqual": "3.5",
        "status": "affected",
        "version": "*",
        "versionType": "git"
      }
    ]
  }
]