fix(common): remove protocol_examples_common

Remaining references to protocol_examples_common are replaced with
references to ESP-IDF.
We will later re-add protocol_examples_common or some equivalent of it
under components/, and release it to the Component Registry.

Author: igrr

ci/check_copyright_config.yaml

@@ -62,4 +62,3 @@ ignore:
    - 'components/esp_modem/port/linux/**'
    - 'components/asio/examples/**'
    - 'components/mdns/**/esp_system_protocols_linux/**'
-   - 'common_components/protocol_examples_common/**'