Always show "30-day ads history" link button in Rewards settings page

[Miyayes]

Description

Currently, when 30-day ads history (or 7-day ads history previously) is empty, the 30-day ads history button/link in the bottom right corner of brave://rewards (Rewards settings page) does not appear.

(Note how it's missing in bottom-right corner.)

This doesn't train users to know that this feature exists.

Solution

1. Always show 30-day ads history link/button, even when list is empty
2. When list is empty, just put a message in there that says "You haven't seen any ads in the last 30 days."

Can get design input as well if needed, but let's iterate. cc: @codybanxs.

[stephendonner]

Verified PASSED using

Brave	1.30.7 Chromium: 92.0.4515.131 (Official Build) nightly (x86_64)
Revision	6b8d6c56ce21e38a72f7c4becb5abc1fa5134f29-refs/branch-heads/4515@{#1933}
OS	macOS Version 11.5.1 (Build 20G80)

Steps:

1. new profile
2. launched Brave
3. clicked Start using Rewards
4. opened brave://rewards
5. confirmed I saw 30-day Ads History link
6. clicked on the link and confirmed I saw No ads viewed in the last 30 days.
7. viewed an ad
8. confirmed I saw the new ad appear after refreshing
9. confirmed Ads I received this month is now 1, as expected too

example	example	example	example

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Verification passed on

Brave	1.30.65 Chromium: 93.0.4577.63 (Official Build) beta (64-bit)
Revision	ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135}
OS	Ubuntu 18.04 LTS

Verified in Polish (PL)

Verified the 30 day history link is shown when there are 0 ads

Verified No ads viewed in the last 30 days. is translated in ads history

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Verification passed on

Brave | 1.30.68 Chromium: 93.0.4577.63 (Official Build) beta (64-bit)
-- | --
Revision | ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135}
OS | Windows 10 OS Version 2009 (Build 19043.1165)

Verified in Kannada locae
Verified the 30 day history link is shown when there are 0 ads

Viewed an Ad and seen the ads history