[Follow up to 28765] Disabling news source using context menu is not unfollowing from news sources list

[Uni-verse]

Description

After upgrading to a new version of the app with brave news v2 enabled, disabling the sources using the long press context menu on NTP will not unfollow sources in the following list.

Follow up to #28765

Steps to reproduce

1. Install 1.48.x
2. Enabled Brave News V2 under brave://flags
3. Enabled News
4. Subscribe to some channels/sources
5. Unfollow Top sources channel (for easier verification)
6. Return to NTP to update the feed
7. Update app to 1.49.x
8. Long press on one of the sources and disable using context menu
9. Open news settings and checking following list

Actual result

newsbug3_0302.mp4

Expected result

Disabling sources should unfollow it in the list.

Issue reproduces how often

Easily

Version/Channel Information:

• Can you reproduce this issue with the current Play Store version? Yes
• Can you reproduce this issue with the current Play Store Beta version? Yes
• Can you reproduce this issue with the current Play Store Nightly version? N/A

Device details

• Install type (ARM, x86): ARM
• Device type (Phone, Tablet, Phablet): Samsung GS 21
• Android version: 13

Brave version

1.49.117, Chromium 111.0.63.50

[fallaciousreasoning]

Possibly a duplicate of #28765?

[Uni-verse]

Possibly a duplicate of #28765?

@fallaciousreasoning Its a follow up due to some issues with unfollowing sources on upgraded profile.

[kjozwiak]

The above requires 1.50.93 or higher for 1.50.x verification 👍

[Uni-verse]

Verified on Samsung GS 21 5G using version:

Brave	1.50.107 Chromium: 112.0.5615.39 (Official Build) beta (64-bit) 
Revision	a0e7b9718a92bcd1cf33b7c95316caff3fc20714-refs/branch-heads/5615@{#753}
OS	Android 13; Build/TP1A.220624.014

Scenario Test Steps:

1. Install 1.50.86 (Beta App)
2. Enabled Brave News V2 under brave://flags
3. Enabled News
4. Subscribe to some channels/sources
5. Unfollow Top sources channel (for easier verification)
6. Return to NTP to update the feed
7. Updated app to 1.50.107 (Beta)
8. Long press on one of the sources and disable using context menu
9. Open news settings and checking following list

news_fix3.mp4