Shield v2 follow-ups

[rebron]

Description

Follow-up issues to address from Shields v2 that landed in 1.39.x
#18630

• blocked Trackers and ads count is shown when the shield is down #22422
• Incorrect favicon is shown when the shield toggle is turned OFF and ON #22415
• Shields panel doesn't always update immediately upon light/dark-mode toggle #22389
• Block scripts heading label should read Blocked scripts #22364
• Global defaults link in the Shields panel is not visible for some screen sizes #22539
• Shields should be disabled for magnet links #22428
• "Look & feel" text should be removed from Shields global settings page #22382

Brave version (brave://version info)

Targeting for 1.41.x

Version/Channel Information:

• Can you reproduce this issue with the current release? yes. 1.38.x
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

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

Miscellaneous Information:

[nullhook]

the IPFS issue is a more involved task and requires approvals from various code owners.
we won't be resolving it in this for now.