Kibana APM Custom links creation don't work

[lzientek]

Kibana version:
7.14
Elasticsearch version:
7.14
Server OS version:
Elastic Cloud
Browser version:
Chrome 92.0.4515.159
Browser OS version:
OS X BigSure
Original install method (e.g. download page, yum, from source, etc.):
Elastic cloud (AWS)
Describe the bug:
When I want to create a new custom url in APM settings but the save button doesn't do anything (no creation, no error, nothing)
Steps to reproduce:

1. Go in apm > settings > Customize App
2. Click on Create a custom link (no custom links are existing)
3. Fill the label filled with google
4. Fill the url filled with https://google.com
5. No filter are filled
6. Click Save > nothing happens

Expected behavior:
The save button works and a new custom link is created

Screenshots (if relevant):

Errors in browser console (if relevant):
None

Provide logs and/or server output (if relevant):
None

Any additional context:

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)