MM-54502 - Update regex to force first character to be alpha (#24675)

Automatic Merge

server/channels/app/plugin_api_test.go

@@ -1425,14 +1425,14 @@ func TestPluginCreateBot(t *testing.T) {
 	api := th.SetupPluginAPI()
 
 	bot, err := api.CreateBot(&model.Bot{
-		Username:    model.NewRandomString(10),
+		Username:    "a" + model.NewRandomString(10),
 		DisplayName: "bot",
 		Description: "bot",
 	})
 	require.Nil(t, err)
 
 	_, err = api.CreateBot(&model.Bot{
-		Username:    model.NewRandomString(10),
+		Username:    "a" + model.NewRandomString(10),
 		OwnerId:     bot.UserId,
 		DisplayName: "bot2",
 		Description: "bot2",