[OSF] Allows opening the work template modal from a slash command (#22246)

Co-authored-by: Mattermost Build <build@mattermost.com>

app/slashcommands/command_templates.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package slashcommands
+
+import (
+	"github.com/mattermost/mattermost-server/v6/app"
+	"github.com/mattermost/mattermost-server/v6/app/request"
+	"github.com/mattermost/mattermost-server/v6/model"
+	"github.com/mattermost/mattermost-server/v6/shared/i18n"
+)
+
+type TemplatesProvider struct {
+}
+
+const (
+	CmdTemplates = "templates"
+)
+
+func init() {
+	app.RegisterCommandProvider(&TemplatesProvider{})
+}
+
+func (h *TemplatesProvider) GetTrigger() string {
+	return CmdTemplates
+}
+
+func (h *TemplatesProvider) GetCommand(a *app.App, T i18n.TranslateFunc) *model.Command {
+	workTemplateEnabled := a.Config().FeatureFlags.WorkTemplate
+	pbActive, err := a.IsPluginActive(model.PluginIdPlaybooks)
+	if err != nil {
+		pbActive = false
+	}
+	hasBoard, err := a.HasBoardProduct()
+	if err != nil {
+		hasBoard = false
+	}
+
+	return &model.Command{
+		Trigger:          CmdTemplates,
+		AutoComplete:     hasBoard && pbActive && workTemplateEnabled,
+		AutoCompleteDesc: T("api.command_templates.desc"),
+		DisplayName:      T("api.command_templates.name"),
+	}
+}
+
+func (h *TemplatesProvider) DoCommand(a *app.App, c request.CTX, args *model.CommandArgs, message string) *model.CommandResponse {
+	// This command is handled client-side and shouldn't hit the server.
+	return &model.CommandResponse{
+		Text:         args.T("api.command_templates.unsupported.app_error"),
+		ResponseType: model.CommandResponseTypeEphemeral,
+	}
+}

i18n/en.json

@@ -1494,6 +1494,18 @@
     "id": "api.command_shrug.name",
     "translation": "shrug"
   },
+  {
+    "id": "api.command_templates.desc",
+    "translation": "Open the create from template window"
+  },
+  {
+    "id": "api.command_templates.name",
+    "translation": "templates"
+  },
+  {
+    "id": "api.command_templates.unsupported.app_error",
+    "translation": "The templates command is not supported on your device."
+  },
   {
     "id": "api.config.client.old_format.app_error",
     "translation": "New format for the client configuration is not supported yet. Please specify format=old in the query string."