[MM-62408] Server Code Coverage with Fully Parallel Tests (#30078)

* TestPool

* Store infra

* Store tests updates

* Bump maximum concurrent postgres connections

* More infra

* channels/jobs

* channels/app

* channels/api4

* Protect i18n from concurrent access

* Replace some use of os.Setenv

* Remove debug

* Lint fixes

* Fix more linting

* Fix test

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix merge

* [MM-62408] Add CI job to generate test coverage (#30284)

* Add CI job to generate test coverage

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix more Setenv usage

* Fix more potential flakyness

* Remove parallelism from flaky test

* Remove conflicting env var

* Fix

* Disable parallelism

* Test atomic covermode

* Disable parallelism

* Enable parallelism

* Add upload coverage step

* Fix codecov.yml

* Add codecov.yml

* Remove redundant workspace field

* Add Parallel() util methods and refactor

* Fix formatting

* More formatting fixes

* Fix reporting

server/channels/app/platform/config_test.go

@@ -18,6 +18,7 @@ import (
 )
 
 func TestConfigListener(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := Setup(t)
 	defer th.TearDown()
 
@@ -53,6 +54,7 @@ func TestConfigListener(t *testing.T) {
 }
 
 func TestConfigSave(t *testing.T) {
+	mainHelper.Parallel(t)
 	cm := &mocks.ClusterInterface{}
 	cm.On("SendClusterMessage", mock.AnythingOfType("*model.ClusterMessage")).Return(nil)
 	th := SetupWithCluster(t, cm)
@@ -106,6 +108,7 @@ func TestConfigSave(t *testing.T) {
 }
 
 func TestIsFirstUserAccount(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := SetupWithStoreMock(t)
 	defer th.TearDown()
 	storeMock := th.Service.Store.(*smocks.Store)
@@ -148,6 +151,7 @@ func TestIsFirstUserAccount(t *testing.T) {
 }
 
 func TestIsFirstUserAccountThunderingHerd(t *testing.T) {
+	mainHelper.Parallel(t)
 	th := SetupWithStoreMock(t)
 	defer th.TearDown()
 	storeMock := th.Service.Store.(*smocks.Store)