Change "no tokens" messaging on BR panel for BAT Points regions

[mattmcalister]

For locales where BAT Points are required, when wallet Balance = 0, change the list of "3 ways to fill your wallet":

1. Delete the heading and the 3 bullets

2. Replace it with a sentence -> "Look for ad notifications as you continue to use Brave. Your BAT Points balance will increase with each ad you view."

Reason: Users can't add funds, and we are unlikely to issue free token grants.

[rebron]

Closing. Duplicate of #6654

[GeetaSarvadnya]

Verification passed on

Brave	0.71.114 Chromium: 78.0.3904.97 (Official Build) (64-bit)
Revision	021b9028c246d820be17a10e5b393ee90f41375e-refs/branch-heads/3904@{#859}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified the test plan from Updating empty wallet message for unsupported regions brave-core#3849

Verification passed on

Brave	0.71.114 Chromium: 78.0.3904.97 (Official Build) (64-bit)
Revision	021b9028c246d820be17a10e5b393ee90f41375e-refs/branch-heads/3904@{#859}
OS	Ubuntu 18.04 LTS

• Verified the test plan from Updating empty wallet message for unsupported regions brave-core#3849

Verification PASSED on macOS 10.15.1 x64 using the following build:

Brave	0.71.114 Chromium: 78.0.3904.97 (Official Build) (64-bit)
Revision	021b9028c246d820be17a10e5b393ee90f41375e-refs/branch-heads/3904@{#859}
OS	macOS Version 10.15.1 (Build 19B88)

• Verified the test plan from Updating empty wallet message for unsupported regions brave-core#3849