Trackers & ads blocked stats is not shown clearly in NTP when a Gradient/Solid color is selected

[GeetaSarvadnya]

Description

Follow up of PR #brave/brave-core#14783
Trackers & ads blocked stats is not shown clearly in NTP when a Gradient color is selected

Steps to Reproduce

1. NA

Actual result:

Expected result:

Trackers & ads blocked stats should be shown clearly in NTP when a Gradient color is selected

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.45.44 Chromium: 105.0.5195.102 (Official Build) nightly (64-bit)
Revision	4c16f5ffcc2da70ee2600d5db77bed423ac03a5a-refs/branch-heads/5195_55@{#4}
OS	Windows 10 Version 21H2 (Build 19044.1889)

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: @simonhong @pes10k @sangwoo108

[GeetaSarvadnya]

The issue is applicable for solid color selction also

[sangwoo108]

Hi, @aguscruiz ! Could you give me some guideline for the state UI? I think we might want to have shadow underneath the UI.

[aguscruiz]

Linking this issue here with the design solution:
#25392 (comment)

[stephendonner]

Verified PASSED using

Brave	1.46.81 Chromium: 107.0.5304.68 (Official Build) beta (x86_64)
Revision	a4e93e89d3b3df1be22214603fba846ad0183ca5-refs/branch-heads/5304@{#991}
OS	macOS Version 11.7.1 (Build 20G918)

Steps:

1. installed 1.46.81
2. launched Brave
3. opened a new-tab page
4. clicked on Customize
5. selected Background Image
6. selected Solid colors
7. chose a few different colors
8. chose a few different gradients

Confirmed I could easily see the Trackers & ads blocked text and count

gradient 1	gradient 2	solid 1	solid 2