fix(usb/cdc_host): Check endpoint pointers before accessing them

[tore-espressif]

Related to issues:

• https://github.com/espressif/esp-idf/issues/12283
• https://github.com/espressif/esp-idf/issues/12503

[github-actions[bot]]

Unit Test Results

  11 files    11 suites   15m 0s :stopwatch:   27 tests   27 :heavy_check_mark: 0 :zzz: 0 :x: 252 runs  252 :heavy_check_mark: 0 :zzz: 0 :x:

Results for commit 450cef79.

:recycle: This comment has been updated with latest results.