Disabled Rewards Settings Pane Icons should be smaller

[ryanml]

These currently display too large and close to the text, it should look more like:

[btlechowski]

@ryanml 0.71.x uses the old icons and I think the old icons are too small. What do you think?

It comparison, this is how 0.73.x looks like with new icons:

[mandar-brave]

@bradleyrichter @ryanml

[btlechowski]

Verification passed on

Brave	0.71.111 Chromium: 78.0.3904.87 (Official Build) (64-bit)
Revision	20c21f4010010f32462ea8e1d6af30cef66d48c8-refs/branch-heads/3904@{#840}
OS	Ubuntu 18.04 LTS

Verified STR from the description, the icons are smaller but they are old icons. Logged #6756

Verified passed with

Brave	0.71.111 Chromium: 78.0.3904.87 (Official Build) (64-bit)
Revision	20c21f4010010f32462ea8e1d6af30cef66d48c8-refs/branch-heads/3904@{#840}
OS	macOS Version 10.13.6 (Build 17G5019)

• Verified STR from description. Per discussion in today's triage mtg, icons will be fixed with Old icons are used in Disabled Rewards Settings #6756
  Rewards On (showing information before page is refreshed)

Rewards toggled Off

Verification passed on

Brave	0.71.113 Chromium: 78.0.3904.87 (Official Build) (64-bit)
Revision	20c21f4010010f32462ea8e1d6af30cef66d48c8-refs/branch-heads/3904@{#840}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified STR from description.

Rewards On (showing information before page is refreshed)

Rewards toggled Off