[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/api4/remote_cluster_test.go

@@ -13,6 +13,7 @@ import (
 )
 
 func TestGetRemoteClusters(t *testing.T) {
+	mainHelper.Parallel(t)
 	t.Run("Should not work if the remote cluster service is not enabled", func(t *testing.T) {
 		th := Setup(t)
 		defer th.TearDown()
@@ -182,6 +183,7 @@ func TestGetRemoteClusters(t *testing.T) {
 }
 
 func TestCreateRemoteCluster(t *testing.T) {
+	mainHelper.Parallel(t)
 	rcWithTeamAndPassword := &model.RemoteClusterWithPassword{
 		RemoteCluster: &model.RemoteCluster{
 			Name:          "remotecluster",
@@ -294,6 +296,7 @@ func TestCreateRemoteCluster(t *testing.T) {
 }
 
 func TestRemoteClusterAcceptinvite(t *testing.T) {
+	mainHelper.Parallel(t)
 	rcAcceptInvite := &model.RemoteClusterAcceptInvite{
 		Name:          "remotecluster",
 		Invite:        "myinvitecode",
@@ -392,6 +395,7 @@ func TestRemoteClusterAcceptinvite(t *testing.T) {
 }
 
 func TestGenerateRemoteClusterInvite(t *testing.T) {
+	mainHelper.Parallel(t)
 	password := "mysupersecret"
 
 	newRC := &model.RemoteCluster{
@@ -482,6 +486,7 @@ func TestGenerateRemoteClusterInvite(t *testing.T) {
 }
 
 func TestGetRemoteCluster(t *testing.T) {
+	mainHelper.Parallel(t)
 	newRC := &model.RemoteCluster{
 		Name:    "remotecluster",
 		SiteURL: "http://example.com",
@@ -540,6 +545,7 @@ func TestGetRemoteCluster(t *testing.T) {
 }
 
 func TestPatchRemoteCluster(t *testing.T) {
+	mainHelper.Parallel(t)
 	newRC := &model.RemoteCluster{
 		Name:        "remotecluster",
 		DisplayName: "initialvalue",
@@ -604,6 +610,7 @@ func TestPatchRemoteCluster(t *testing.T) {
 }
 
 func TestDeleteRemoteCluster(t *testing.T) {
+	mainHelper.Parallel(t)
 	newRC := &model.RemoteCluster{
 		Name:        "remotecluster",
 		DisplayName: "initialvalue",