Flatpak version does not follow user preferences for terminal colors

### What Happened?

The color palette in the terminal pane differs from the native Terminal app and is generally less readable.

### Steps to Reproduce

Run Flatpak and look at terminal pane.

### Expected Behavior

The terminal pane should use the same colors as the Terminal app (when running on elementaryos at least) or failing that use readable colors.

### OS Version

8.x (Circe)

### OS Architecture

amd64 (on most hardwares)

### Session Type

Secure Session (Wayland, This is the default)

### Software Version

Latest release (I have run all updates)

### Log Output

```shell

```

### Hardware Info

_No response_

首先，在 elementary OS 8.x 上的 Flatpak 构建中复现该问题，并将终端窗格与原生 Terminal 应用进行比较。跟踪终端窗格如何获取其颜色调色板和用户偏好设置；完成的标准是其颜色遵循预期的偏好设置，或始终具有良好的可读性。

由索引模型根据 Issue 内容生成。