thank you banner shows generic favicon instead of custom publisher image

[LaurenWags]

Description

When a publisher has the custom tipping banner configured, the banner is showing the publisher's custom images. However, on the 'Thank You' banner, the generic favicon is used, not the publisher's custom favicon.

Steps to Reproduce

1. Navigate to a site with a custom tipping banner set up (kjozwiak.github.io is what I used)
2. Click on BAT logo, click Send a Tip
3. Verify site has custom favicon (round) image
4. Choose a tip amount and Send My Tip

Actual result:

Thank you Banner displays and shows generic image:

Expected result:

Thank you banner shows custom image from the tipping banner (round image below)

Reproduces how often:

Easily

Brave version (brave://version info)

Brave	0.58.16 Chromium: 71.0.3578.98 (Official Build) (64-bit)
Revision	15234034d19b85dcd9a03b164ae89d04145d8368-refs/branch-heads/3578@{#897}
OS	Mac OS X

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? n/a
• Is the issue reproducible on the latest version of Chrome? n/a

Additional Information

[GeetaSarvadnya]

Verification passed on

Brave	0.60.23 Chromium: 72.0.3626.96 (Official Build) beta (64-bit)
Revision	84098ee7ef8622a9defc2ef043cd8930b617b10e-refs/branch-heads/3626@{#836}
OS	Windows 10

• Verified the STR mentioned in the issue

Verification passed on

Brave	0.60.28 Chromium: 72.0.3626.96 (Official Build) beta (64-bit)
Revision	84098ee7ef8622a9defc2ef043cd8930b617b10e-refs/branch-heads/3626@{#836}
OS	Linux

Verification PASSED on macOS 10.14.2 x64 using the following build:

Brave	0.60.44 Chromium: 72.0.3626.109 (Official Build) (64-bit)
Revision	fae8db7ab9280fa6704a59980263c804f809ebd5-refs/branch-heads/3626@{#857}
OS	Mac OS X