Brave Ads notification always uses release channel icon

[srirambv]

Description

Ad notification uses release channel icon

Steps to Reproduce

1. Install Dev(0.64.36)/Beta(0.63.31)
2. Enable Rewards/Ads
3. Finish ad trigger critera and wait for the ad to show up
4. Ad uses release channel icon instead of Dev/Beta respectively

Actual result:

Expected result:

Should use respective channel icon to differentiate which channel build is showing ad notification

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	0.63.31 Chromium: 73.0.3683.75 (Official Build) beta(64-bit)
Revision	909ee014fcea6828f9a610e6716145bc0b3ebf4a-refs/branch-heads/3683@{#803}
OS	Linux

Brave	0.64.36 Chromium: 73.0.3683.75 (Official Build) dev(64-bit)
Revision	909ee014fcea6828f9a610e6716145bc0b3ebf4a-refs/branch-heads/3683@{#803}
OS	Linux

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds?
  Yes

Website problems only:

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

Additional Information

Also too small icon similar to #2887
cc: @tmancey @bridiver

[tmancey]

Blocked as issue will be closed once #9592 has been implemented

[tmancey]

Closing issue as superseded by #9592