Fix +/- add new filter buttons when changing data using teal_data_module

[vedhav]

Fixes the +/- icon behavior on the filter panel.
Please checkout to the fix-add-remove-ui@669_insertUI@main in both teal and teal.slice
In teal.slice it just reverts one commit to the working version of the show/hide logic.

When the data changes using teal_data_module the filter panel observers are being called once again thus running the scope of the observers as many times the data changes.
The fix is to reinitialize the filter panel with new NS so the observers are not connected to the active UI anymore.

Example app to test

pkgload::load_all("teal.slice")
pkgload::load_all("teal")
library(MultiAssayExperiment)

data <- teal::teal_data_module(
  ui = function(id) {
    ns <- shiny::NS(id)
    shiny::tagList(
      shiny::textInput(ns("username"), label = "Username"),
      shiny::passwordInput(ns("password"), label = "Password"),
      shiny::actionButton(ns("submit"), label = "Submit")
    )
  },
  server = function(id, ...) {
    shiny::moduleServer(id, function(input, output, session) {
      shiny::eventReactive(input$submit, {
        data <- teal.data::teal_data() |>
          within(
            {
              logger::log_debug("Loading data...")
              iris <- iris
              data("miniACC", package = "MultiAssayExperiment", envir = environment())
            },
            username = input$username,
            password = input$password
          )
        data
      })
    })
  },
  once = FALSE
)

app <- init(
  data = data,
  modules = example_module()
)

shiny::runApp(app$ui, app$server)

[gogonzo]

This will complicate testing a little bit. What are the alternatives?
Why not to make a PR to teal.slice so we can discuss those changes?

[vedhav]

Raised the PR in teal.slice. (It is just reverting one commit. So, changes over there are not relevant to the fix.)
But, this solves a wider issue of not having to call multiple observers, without this all the observers in the srv_active are being called as many times as the filter module is initialized.
The alternative would be to implement the observer destroying logic we use in FilterState by storing the observers and destroying them. However, we might have to make that observer public as we need to trigger the destroy in teal when we call this module.

[vedhav]

Closing this as the multiple observers issue is fixed by destroying the observers in teal.slice.