Sidebar UI should be hidden only when tab-initiated full screen

[simonhong]

Description

On macOS, sidebar UI is hidden when browser enters full screen mode. (ex, via green maximize button)
Sidebar only should not be visible when browser is in fullscreen by tab. (ex, youtube video fullscreen mode)

Steps to Reproduce

1. Enable sidebar feature via brave://flags relaunch
2. Check sidebar is visible
3. Maximize browser on macOS
4. Check sidebar is visible

Actual result:

Sidebar is hidden after browser is maximized

Expected result:

Sidebar should not be hidden in maximized mode.

Reproduces how often:

Easy

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

[kjozwiak]

The above will require 1.44.68 or higher for 1.44.x verification 👍

[stephendonner]

Verified PASSED using

Brave	1.44.73 Chromium: 105.0.5195.68 (Official Build) beta (x86_64)
Revision	ad13e82529051bac6a0e65f455e6d7a1e5fd7938-refs/branch-heads/5195@{#903}
OS	macOS Version 13.0 (Build 22A5331f)

Steps:

1. installed 1.44.78
2. launched Brave
3. ensure the sidebar was visible by default
4. maximized the window

Confirmed the sidebar was retained in full-screen mode

1.44.73	1.43.88

Also ensured that the sidebar was hidden in YouTube's fullscreen mode

YouTube, default	YouTube, fullscreen