Turn focalboard plugin on by default (#18132)

* turn focalboard plugin on by default

* cleanup

* update config diff tests to add new default

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/config.go

@@ -2713,6 +2713,11 @@ func (s *PluginSettings) SetDefaults(ls LogSettings) {
 		s.PluginStates["com.mattermost.plugin-channel-export"] = &PluginState{Enable: true}
 	}
 
+	if s.PluginStates["focalboard"] == nil {
+		// Enable the focalboard plugin by default
+		s.PluginStates["focalboard"] = &PluginState{Enable: true}
+	}
+
 	if s.EnableMarketplace == nil {
 		s.EnableMarketplace = NewBool(PluginSettingsDefaultEnableMarketplace)
 	}