remove line for Total from wallet

[LaurenWags]

Test Plan

Please follow the test plan outlined under #1297 (comment).

Original Reported Issue

Description

Per discussion it was decided to remove the line item for 'Total' from the current Rewards Summary display (to be renamed per #1296).

This info is accessible from the Wallet panel/container on Brave Rewards Main Page as well as on the Brave Rewards Panel (accessible from BAT logo in URL bar).

cc @davidtemkin @kjozwiak @srirambv @NejcZdovc @jenn-rhim @mandar-brave

[kjozwiak]

@LaurenWags mind adding some test cases into the original issue and adding the QA/Test-Plan-Specified label? Thanks!

[LaurenWags]

Test Plan:
Navigate to chrome://rewards
Enable Brave Rewards if not already enabled
Look at the Wallet panel --> Verify line for total is removed
Click on the BAT logo in URL bar. --> Verify line for total is removed

[srirambv]

Verification Passed on

Brave	0.55.12 Chromium: 70.0.3538.45 (Official Build) beta (64-bit)
Revision	cbdc32e4334458954e9def214d7e5fa1ca1960eb-refs/branch-heads/3538@{#830}
OS	Linux

Verified passed with

Brave	0.55.12 Chromium: 70.0.3538.45 (Official Build) beta(64-bit)
Revision	cbdc32e4334458954e9def214d7e5fa1ca1960eb-refs/branch-heads/3538@{#830}
OS	Mac OS X

Verification passed on

Brave	0.55.12 Chromium: 70.0.3538.45 (Official Build) (64-bit)
Revision	cbdc32e4334458954e9def214d7e5fa1ca1960eb-refs/branch-heads/3538@{#830}
OS	Windows 7