Disable Bookmarks & Reading list buttons on the sidebar in Guest window

[MadhaviSeelam]

Description

Found while testing #31644

Steps to Reproduce

1. Install 1.62.32
2. launch Brave
3. click Hamburger >> More tools >> Open Guest profile
4. click on Bookmarks button on the sidebar

Actual result:

Expected result:

Disable to Bookmarks & Reading list buttons on the sidebar in the Guest window```

Reproduces how often:

Easily

Brave version (brave://version info)

Brave | 1.62.32 Chromium: 119.0.6045.105 (Official Build) nightly (64-bit)
-- | --
Revision | 76f975d47c49751a29f222762c1a24bd7df88cef
OS | Windows 11 Version 22H2 (Build 22621.2428)

Version/Channel Information:

• Can you reproduce this issue with the current release? N/A
• Can you reproduce this issue with the beta channel? N/A
• Can you reproduce this issue with the nightly channel? Yes

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:

@rebron @aguscruiz

[stephendonner]

Verified PASSED using

Brave | 1.62.38 Chromium: 119.0.6045.134 (Official Build) nightly (x86_64)
-- | --
Revision | 63d368dd4d01900c1f3f056b6371210d10899d5a
OS | macOS Version 14.2 (Build 23C5041e)

First, reproduced using 1.61.32:

example	example

Then, confirmed that Bookmarks and Reading List buttons are disabled when in a Guest window/profile

example	example