CR90 - Icon used in the Guest mode button is not as per the brave brand

[GeetaSarvadnya]

Description

The icon used in the Guest mode button is not as per the brave brand

Steps to Reproduce

1. Open brave 1.24.29
2. Click on the hamburger menu and select Create a New Profile
3. Click on the profile icon and navigate to Manager Profiles settings
4. Look for Guest mode button

Actual result:

Expected result:

Icon should match the Guest window icon of Brave

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.24.29 Chromium: 90.0.4430.41 (Official Build) nightly (64-bit)
Revision	e9c92b1eaca8487e212f3f6bc081fdb6d4863759-refs/branch-heads/4430@{#723}
OS	Windows 10 OS Version 2004 (Build 19041.867)

Version/Channel Information:

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

Other Additional Information:

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

Miscellaneous Information:

cc: @brave/legacy_qa @mkarolin @rebron

[LaurenWags]

cc @karenkliu also

[aguscruiz]

I updated the icon design here:
https://www.figma.com/file/sS3l8tqUFxt54MEiBTalUI/Desktop-toolbar-and-menu?node-id=1575%3A23108

A few notes:

• I noted the the screenshot above doesn't have the "guest mode" button anymore, it seems that you can only access through the profile pic dropdown
• I'm using the outlined version of the icon, since that's the style we're using currently and moving forward.
• Private windows uses the same color icon as dark mode window

Screenshots:

[aguscruiz]

@rebron in case you want to tackle this in a future release, it should only be an icon change, as far as I can tell