Refactor more code to use testutils.WasCalled (#13054)

* Refactor more code to use testutils.WasCalled

* incorporate review comments

* Revert watcher_test.go changes

The file is in config package and the other tests use config_test.
So it is not visible.

utils/testutils/testutils.go

@@ -8,7 +8,6 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"time"
 
 	"github.com/mattermost/mattermost-server/utils/fileutils"
 )
@@ -28,15 +27,3 @@ func ReadTestFile(name string) ([]byte, error) {
 		return data.Bytes(), nil
 	}
 }
-
-// WasCalled reports whether a given callback channel was called
-// within the specified time duration or not.
-func WasCalled(c chan bool, duration time.Duration) bool {
-	wasCalled := false
-	select {
-	case <-c:
-		wasCalled = true
-	case <-time.After(duration):
-	}
-	return wasCalled
-}