News feed should not show ad notification when no source is selected

[srirambv]

Description

News feed should not show ad notification when no source is selected

Steps to Reproduce

1. Disable all source for news fee
2. Open a new tab
3. Ad is shown when it says no content to show

Actual result:

Expected result:

No ad when there is no feed

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.47.75 Chromium: 108.0.5359.40 (Official Build) nightly (64-bit)
Revision	280b5fcaab3e877562b06cfaf2eb51121e13c3b9-refs/branch-heads/5359@{#689}
OS	Windows 11 Version 22H2 (Build 22621.819)

## Version/Channel Information:

• Can you reproduce this issue with the current release? Not checked
• Can you reproduce this issue with the beta channel? Not checked
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? NA
• Does the issue resolve itself when disabling Brave Rewards? NA
• Is the issue reproducible on the latest version of Chrome? NA

Miscellaneous Information:

cc: @mattmcalister @petemill @brave/qa-team @fallaciousreasoning

[ghost]

Brave News should also not show Brave Ads when Brave Rewards Ads is disabled.

[fallaciousreasoning]

This is in Feed V1, so it should be fixed automatically by #34593