rewards onboarding text doesn't match design

[LaurenWags]

Description

Starting in 1.20.x if you visit brave://rewards without being opt-ed into BR, you should see the below per Figma design from brave/brave-core#7170 / https://www.figma.com/file/0dbMYs8Wp8W3RgrG1yTdki/RE-1.0?node-id=2236%3A30931.

The implemented text on this page differs from the figma design above.

Steps to Reproduce

1. Clean profile 1.20.x
2. Navigate to brave://rewards

See also #13896 (comment) re: onboarding modal from panel.

Actual result:

1. Ampersand used instead of and
2. Text differs
3. Button text differs

Expected result:

From Figma:

Reproduces how often:

easily

Brave version (brave://version info)

Brave	1.20.96 Chromium: 88.0.4324.96 (Official Build) beta (x86_64)
Revision	68dba2d8a0b149a1d3afac56fa74648032bcf46b-refs/branch-heads/4324@{#1784}
OS	macOS Version 10.15.7 (Build 19H15)

Brave	1.21.38 Chromium: 88.0.4324.96 (Official Build) nightly (x86_64)
Revision	68dba2d8a0b149a1d3afac56fa74648032bcf46b-refs/branch-heads/4324@{#1784}
OS	macOS Version 10.15.7 (Build 19H15)

Version/Channel Information:

• Can you reproduce this issue with the current release? n/a 1.19.x
• Can you reproduce this issue with the beta channel? yes 1.20.x
• Can you reproduce this issue with the nightly channel? yes 1.21.x

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 @codybanxs @brave/legacy_qa @rebron

[LaurenWags]

cc @codybanxs - when the text on brave://rewards is updated, should the panel have that same text? this is what is shown in 1.20.x: