brave://welcome page background needs to be adjusted for RTL languages

[LaurenWags]

Description

Found while testing #3574

Background of the brave://welcome page for right to left languages (such as Hebrew or Arabic) doesn't match those of left to right languages (English, etc).

When brave://welcome is displayed for a RTL language, the background image is only on half the page. Additionally, when you go thru the onboarding pages, the background is white, so you have a white box on a white background.

Steps to Reproduce

1. Set language to a RTL one such as Arabic or Hebrew
2. Clean profile, launch Brave

Actual result:

See how background is on half the page. Additionally, as you move thru the flow, the background is white on each box.

Expected result:

Should be like the LTR languages:

Reproduces how often:

easily

Brave version (brave://version info)

Brave	0.66.101 Chromium: 75.0.3770.142 (Official Build) (64-bit)
Revision	8d93477bd18154c67a70a67019cb8032382c55dd-refs/branch-heads/3770@{#1160}
OS	Mac OS X

Brave	0.67.112 Chromium: 76.0.3809.62 (Official Build) beta (64-bit)
Revision	7b77856b3aa34d72f246d12340fc1ded8b2c0e83-refs/branch-heads/3809@{#798}
OS	Mac OS X

Version/Channel Information:

• Can you reproduce this issue with the current release? yes
• Can you reproduce this issue with the beta channel? yes
• Can you reproduce this issue with the dev channel? unsure but probably
• Can you reproduce this issue with the nightly channel? unsure but probably

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:

[rebron]

cc: @rossmoody I believe this was fixed in 70.x?

[rossmoody]

I'd say this is worth closing because the background doesn't exist like that anymore.

[rebron]

Closing. Fixed in 70.x

[GeetaSarvadnya]

Verification passed on

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified the STR from the description
• Logged Search box is overlapping on Search Setting text in RTL languages #6129

Verified passed with

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	macOS Version 10.13.6 (Build 17G5019)

• Verified STR from description.

Verification passed on

Brave	0.69.128 Chromium: 77.0.3865.75 (Official Build) (64-bit)
Revision	201e747d032611c5f2785cae06e894cf85be7f8a-refs/branch-heads/3865@{#776}
OS	Ubuntu 18.04 LTS

• Verified STR from description.