Remove testing of old mbed-cloud-client-example with SOTP

[MarceloSalazar]

Page link

https://os.mbed.com/docs/mbed-os/v6.2/porting/testing-with-the-demo-applications.html

Expected to find...

Mbed OS example apps and up to date info.

Found

Old mbed-cloud-client-example with instructions on how to enable SOTP, which was deprecated some time ago in Mbed OS 5.

There is content in the mbed-os-example-pelion docs that's up to date.

[ciarmcom]

Thank you for raising this detailed GitHub issue. I am now notifying our internal issue triagers.
Internal Jira reference: https://jira.arm.com/browse/IOTDOCS-1611