Running `mix phx.gen.presence` in umbrella app uses wrong PubSub.

[pauldemarco]

Environment

• Elixir version (elixir -v): Elixir 1.18.3
• Phoenix version (mix deps): 1.7.21
• Operating system: Mac

Actual behavior

Running mix phx.gen.presence from within an umbrella app apps/hello_web generates this:

defmodule HelloWeb.Presence do
  use Phoenix.Presence,
    otp_app: :hello_web,
    pubsub_server: HelloWeb.PubSub # <-- This is wrong PubSub
end

Expected behavior

It should use the correct PubSub from main app:

defmodule HelloWeb.Presence do
  use Phoenix.Presence,
    otp_app: :hello_web,
    pubsub_server: Hello.PubSub
end

[pauldemarco]

Also, in apps/hello_web/test/support/channel_case.ex:

  setup tags do
    HelloWeb.DataCase.setup_sandbox(tags) # <-- should be Hello.DataCase
    :ok
  end

[josevalim]

Can you please send a PR?