[Android] Hide UI elements related to IdleDetection

[mkarolin]

Split out Android from #18409.

Following up from #18269 (comment), Brave currently disables the Idle Detection API, but doesn't remove the UI elements / settings around it, causing confusion.

To prevent confusion, we should just hide the UI elements related to the Idle Detection API

[kjozwiak]

Looks like this working as expected on Android. Went through the following verification/checks using the following build:

Nightly 1.32.44 Chromium: 94.0.4606.71

Case #1 - IdleDetection disabled

• checked https://idle-detection.glitch.me and ensured that the Idle Detection API is disabled
• verified that there's no UI associated with Idle Detection visible under Settings -> Site Settings
• verified that there's no UI associated with Idle Detection visible under Settings -> Site Settings -> All Sites

Example	Example	Example	Example

Case #2 - IdleDetection enabled

• launched Brave using --enable-features=IdleDetection
• ensured that visiting https://idle-detection.glitch.me allows you to enable the Idle Detection API
• ensured that enabling the Idle Detection API displays a permission modal
• ensured that Your device use appears under All Sites under Site Settings for https://idle-detection.glitch.me
• ensured disabling Idle Detection by removing --enable-features=IdleDetection removes the UI from All Sites

Example	Example

Closing this of after speaking with @mkarolin & @SergeyZhukovsky. We'll also QA the above on Android via #18409.