Update mbed-coap to version 4.4.4

[anttiylitokola]

Description

Fixes one error: IOTCLT-2638 Hardfault during reconnection retry with Thread

Pull request type

[x] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[anttiylitokola]

@yogpan01, @TeroJaasko, please review

[yogpan01]

Approved.
@0xc0170 @adbridge Can you please take this in for mbed-os-5.8.6 release?
This fixes critical issue for mbed-cloud-client hardfaulting on Thread devices.

[adbridge]

@yogpan01 Code freeze for 5.8.6 was yesterday! I will try and get this in but I make no promises. Please remind your team that we are going to start refusing PRs that miss deadlines in the future...

[adbridge]

/morph build

[adbridge]

/morph build

[adbridge]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2217
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7082/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Build : SUCCESS

Build number : 2218
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7082/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Build : SUCCESS

Build number : 2219
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7082/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[cmonr]

Restarting the export job.
/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1847
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7082/

[cmonr]

CI went through an accidental outage on Friday. Looks like this test wasn't restarted.

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2018
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7082/2018

[adbridge]

Looks like this one didn't make it to 5.9! Adding in to 5.9.2