sometimes TAP image isn't shown

[LaurenWags]

Test plan

See brave/brave-core#5243

Description

Sometimes the image isn't shown on the TAP message box on brave://rewards. Page refresh fixes it.

Steps to Reproduce

This is one scenario where I've noticed it, maybe there are others.

1. Clean profile, US locale, staging env
2. Enable Rewards
3. Connect a KYC'd user wallet

Actual result:

When you're directed back to brave://rewards, look at the TAP message box

If you refresh the page, image shows

Expected result:

Image should be displayed in the box

Reproduces how often:

easily

Brave version (brave://version info)

Brave	1.7.81 Chromium: 80.0.3987.149 (Official Build) dev (64-bit)
Revision	5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS	macOS Version 10.14.6 (Build 18G3020)

Version/Channel Information:

• Can you reproduce this issue with the current release? n/a
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the dev channel? yes
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

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

Miscellaneous Information:

cc @rebron @brave/legacy_qa

[NejcZdovc]

cc @ryanml

[LaurenWags]

Verified using

Brave	1.9.49 Chromium: 81.0.4044.129 (Official Build) dev (64-bit)
Revision	3d71af9f5704a40b85806f4d08925db24605ba25-refs/branch-heads/4044@{#979}
OS	macOS Version 10.14.6 (Build 18G3020)

• Issue as originally reported in description still reproduces. Logged follow up issue [Desktop] sometimes images are not being displayed for promo cards under "brave://rewards" - follow up to 8964 #9553

Verification passed on

Brave	1.9.52 Chromium: 81.0.4044.129 (Official Build) dev (64-bit)
Revision	3d71af9f5704a40b85806f4d08925db24605ba25-refs/branch-heads/4044@{#979}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified the STR from the description

Verification passed on

Brave	1.9.62 Chromium: 81.0.4044.138 (Official Build) dev (64-bit)
Revision	8c6c7ba89cc9453625af54f11fd83179e23450fa-refs/branch-heads/4044@{#999}
OS	Ubuntu 18.04 LTS

• Verified the STR from the description