[MM-15490] Rework default password requirements (#10844)

* Rework default password requirements

* Update API Test Lib Default User PW

* Remove unused function; Disable password reqs in dev mode

* Disable strict password requirements for unit tests

* Update unit tests

utils/password.go

@@ -10,14 +10,6 @@ import (
 	"github.com/mattermost/mattermost-server/model"
 )
 
-func IsPasswordValid(password string) *model.AppError {
-	if len(password) > model.PASSWORD_MAXIMUM_LENGTH || len(password) < model.PASSWORD_MINIMUM_LENGTH {
-		return model.NewAppError("User.IsValid", "model.user.is_valid.pwd.app_error", map[string]interface{}{"Min": model.PASSWORD_MINIMUM_LENGTH}, "", http.StatusBadRequest)
-	}
-
-	return nil
-}
-
 func IsPasswordValidWithSettings(password string, settings *model.PasswordSettings) *model.AppError {
 	id := "model.user.is_valid.pwd"
 	isError := false