New tab page overflow

[rossmoody]

Test plan

See #5038 (comment)

Description

New tab page is getting scrollbars from overflow around 920px -> 1120px widths. Should have it just be responsive without the scrollbars.

[imptrx]

Test Plan:

1. Open New tabs page
2. Slowly shrink window and see if horizontal/vertical scroll bars appear

Note: Beyond a certain size, shrinking will always produce vertical scroll bars since the page doesn't fit the elements

[imptrx]

Closed by: brave/brave-core#2566 as it pulled in the fix from brave-ui.

[btlechowski]

Verification passed on

Brave	0.69.119 Chromium: 76.0.3809.132 (Official Build) beta (64-bit)
Revision	fd1acc410994a7a68ac25bc77513d443f3130860-refs/branch-heads/3809@{#1035}
OS	Windows 7 Service Pack 1 (Build 7601.24494)

Verified test plan from #5038 (comment)

Logged #5844

Verification passed on

Brave	0.69.121 Chromium: 76.0.3809.132 (Official Build) beta (64-bit)
Revision	fd1acc410994a7a68ac25bc77513d443f3130860-refs/branch-heads/3809@{#1035}
OS	Ubuntu 18.04 LTS

Verified test plan from #5038 (comment)

Encountered #5844

Verification PASSED on macOS 10.14.6 x64 using the following build:

Brave	0.69.121 Chromium: 76.0.3809.132 (Official Build) beta (64-bit)
Revision	fd1acc410994a7a68ac25bc77513d443f3130860-refs/branch-heads/3809@{#1035}
OS	Mac OS X