Ads Rewards Grants - expiration date in UI - follow up to 4042

[LaurenWags]

Description

Ad grants still displaying expiration date on UI from both brave://rewards page and panel when viewing the grants list (which contains both UGP and Ad grants).

Steps to Reproduce

1. Claim an Ad grant. Note, on the "It's your lucky day" screen there isn't a date.
2. Navigate to brave://rewards or open panel.
3. Click on 'Grants' button.

Actual result:

Expiration date is displayed:

Expected result:

No expiration date (like on "It's your lucky day" screen:

Reproduces how often:

easily

Brave version (brave://version info)

Brave	0.63.45 Chromium: 74.0.3729.75 (Official Build) beta(64-bit)
Revision	fdb7915642fef8cf997beac2554709d148e3c187-refs/branch-heads/3729@{#754}
OS	Mac OS X

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? unsure
• Can you reproduce this issue with the nightly channel? unsure

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:

cc @mandar-brave @NejcZdovc @jsecretan

[btlechowski]

Reproduced on

Brave	0.63.45 Chromium: 74.0.3729.75 (Official Build) beta (64-bit)
Revision	fdb7915642fef8cf997beac2554709d148e3c187-refs/branch-heads/3729@{#754}
OS	Windows 10 OS Build 17134.523

[GeetaSarvadnya]

Verification passed on

Brave	0.63.52 Chromium: 74.0.3729.131 (Official Build) (64-bit)
Revision	518a41c1fa7ce1c8bb5e22346e82e42b4d76a96f-refs/branch-heads/3729@{#954}
OS	Windows 10 OS Build 17134.523

• Verified the test plan from Removes date from ads grants in the wallet brave-core#2337

Verified passed with

Brave	0.63.55 Chromium: 74.0.3729.131 (Official Build) (64-bit)
Revision	518a41c1fa7ce1c8bb5e22346e82e42b4d76a96f-refs/branch-heads/3729@{#954}
OS	Mac OS X

• Verified test plan from Removes date from ads grants in the wallet brave-core#2337
• Verified Ad grants do not display expiration dates
  
  
  
• Verified UGP grants still display expiration dates:
  
  

Verification PASSED on Ubuntu 18.04.2 LTS x64 using the following build:

Brave	0.63.55 Chromium: 74.0.3729.131 (Official Build) (64-bit)
Revision	518a41c1fa7ce1c8bb5e22346e82e42b4d76a96f-refs/branch-heads/3729@{#954}
OS	Linux

• Verified the test plan outlined under Removes date from ads grants in the wallet brave-core#2337