in R shiny, how to fix error in sourcing app as nothing changes when clicking on action button?

Building on multiple stackoverflow questions, I tried to build this app which contain two action buttons the first one shows datatable the second one should open another sourced app but actaully nothing changes but in the global environment all list, functions and dataframes are reflecting.
the used code.

#UI.R--------------------------------

library(shiny)
library(shinydashboardPlus)
library(DT)
library(readxl)
library(dplyr)
library(formattable)
library(shinydashboard)
library(shinyjqui)
library(shinyjs)
library(shinythemes)
library(markdown)

title <- "emblem"
ui = fluidPage(theme=shinytheme("superhero"),
           dashboardPage(dashboardHeader(title = title, titleWidth = 200), 
                         dashboardSidebar(selectInput("listofitems","Items List",c("Home","Group","Clients"), selected = "Home")),
                         dashboardBody(
                             useShinyjs(),
                             uiOutput("ui_myHome"))))

#SERVER.R
Clientsbutton<-fluidPage(theme=shinytheme("yeti"),

                     DT::dataTableOutput("mytable"))
shinyServer(function(input, output, session){
output$mytable = DT::renderDataTable({
    mtcars
})
    output$ui_myHome<-renderUI({
        if (input$listofitems == 'Home'){(fluidPage(
            widgetUserBox(title = "Clients",
                          shiny::actionButton(inputId='clientsmainbuttonId', label="Click here"),
                          type = 2, src = "https://adminlte.io/themes/AdminLTE/dist/img/user7-128x128.jpg", color = "yellow"),
            widgetUserBox(title = "Group",
                          shiny::actionButton(inputId='GroupbuttonId', label="Click here"),
                          type = 2, src = "https://adminlte.io/themes/AdminLTE/dist/img/user7-128x128.jpg", color = "green")))}
        
        else if (input$listofitems == 'Clients'){(Clientsbutton)}
        else if (input$listofitems == 'Group'){(source("testsource.R",local = T)$value)}
    })
    observeEvent (input$GroupbuttonId,{
        #browser
        source("testsource.R",local = T)$value
    })
    observeEvent(input$clientsmainbuttonId,{updateSelectInput(session,"listofitems","Items List",         choices =c("Home","Group","Clients"), selected = "Clients")},ignoreInit = TRUE)
    observeEvent(input$logo,{updateSelectInput(session,"listofitems","Items List", choices =c("Home","Group","Clients"), selected = "Home")},ignoreInit = TRUE)
})

#TO BE SOURCED APP
File name testsource.R

rm(list = ls())
library(shiny)

shinyApp(
ui=shinyUI(basicPage(
actionButton("go", "Go"),
numericInput("n", "n", 50),
plotOutput("plot")
 )),
server=shinyServer(function(input, output, session){

randomVals <- eventReactive(input$go, {
  runif(input$n)
})

output$plot <- renderPlot({
  hist(randomVals())
})
}) 
)