Borderless panes get border when resized, when using a `default_tab_template`

[aemogie]

2. Issues with the Zellij UI / behavior

Issue description

When using a layout with a default_tab_template that contains children and another pane (with just children, this bug doesn't happen). This also doesn't happen when you have multiple children in the tab template (Refer to Video)

Minimal reproduction

1. Open Zellij with the following layout.

layout {
  default_tab_template {
    pane
    children
  }
  tab {
    pane borderless=true
  }
}

2. Resize the terminal
3. The borderless pane suddenly has a border.
4. Create a new pane
5. Resize again
6. The pane is back to being borderless.

Video

Video of reproduction on my local machine, in case I missed some details. (On YouTube, as GitHub doesn't allow files larger than 10MB)

Other relevant information

Compiled from tag v0.39.2