[MM-24753] Improves error message when plugin crashes during slash command (#15334)

Co-authored-by: Ali Farooq <ali.farooq0@pm.me>
Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

plugin/environment.go

@@ -472,8 +472,8 @@ func (env *Environment) RunMultiPluginHook(hookRunnerFunc func(hooks Hooks) bool
 	}
 }
 
-// performHealthCheck uses the active plugin's supervisor to verify if the plugin has crashed.
-func (env *Environment) performHealthCheck(id string) error {
+// PerformHealthCheck uses the active plugin's supervisor to verify if the plugin has crashed.
+func (env *Environment) PerformHealthCheck(id string) error {
 	p, ok := env.registeredPlugins.Load(id)
 	if !ok {
 		return nil