Race condition in loading contacts can cause previously selected contact to load

[dianabarsan]

Describe the bug
Contacts page could end up loading the previously loaded contact if a contact change is received just prior to the contact being de-selected.

To Reproduce
This is very hard to reproduce with actual usage, but it has been causing a wdio e2e test to fail intermittently.
Example of failure is: https://github.com/medic/cht-core/runs/3297387483?check_suite_focus=true#step:18:282
This failure is quite common (once every 10 suites?).

Expected behavior
The selected contact shouldn't be changed the the previously selected contact.

Environment

• Instance: GHA Virtual machine
• App: webapp
• Version: 3.12

Additional context
I added helper logs in the code, so I better understand what's going on, and reran the test locally until I got a failure. This is what is happening:

routing to contact "health_center_uuid"
selecting contact "health_center_uuid"
set selected contact "health_center_uuid"
contact receives external change "health_center_uuid"
selecting contact "health_center_uuid"
set selected contact null <- navigating away from the contact content page, in the case of the test, we route to contact-edit to add a new contact
set selected contact "health_center_uuid" <- the callback from the external change contact load updates the state with the old contact, so the next time we load the contacts content component, the state is actually dirty!
routing to contact "clinic_uuid" <- loading another contact 
selecting contact "clinic_uuid"
contact receives external change "health_center_uuid" <- because the state is dirty when we load the component, the code reacts to a change of the previously selected contact
selecting contact "health_center_uuid"
set selected contact "clinic_uuid"
set selected contact "health_center_uuid"

[dianabarsan]

I just realized I had already created an issue for the flaky e2e test:#7244

[latin-panda]

This is how I was able to see the problem:

• login as an online user
• set the network slow
• watch the log of actions to see the value of selectedContact in Store
• move from "contact view" to "contact edit", back and forth many times and quickly, but at the end land in "contact edit"
• make sure you've waited for all the logs to finish printing.
• observe when in "contact edit page" the selectedContact from the store is set to the last contact view data. The expected is to be null.

I've provided a fix here, see the logs after fix:

[latin-panda]

Merged