Add RSS support for Brave News on Android

[alexsafe]

Description

Brave News should support custom sources from RSS feeds.
Original specs found here https://docs.google.com/document/d/1X9lA00zHa8pKol63i0O23LA4UcSHDYoagIOH2DqwljI/edit#heading=h.pu0c9s6h0f0z

Steps to reproduce

1. Go to Brave News settings and activate it
2. Notice the Your Sources / Add source added to the list of preferences
3. 
4. Tap on Add source and type an Rss feed URL - ex. https://www.theguardian.com/uk/sport/rss
   For more feed examples you can search in the slack news channel if needed. There are some examples given there
   (has to be the exact feed, multiple feed support will be added in a different issue)
5. Hit Search and the feed should be added to the Your Sources section
   
6. Close the settings and hit the Load more content button that should be there
7. Scroll until you find a source having the publisher as Sport|The Guardian (in the example above), obviously smth similar in case of other sources (I had to scroll a bit for it to appear sometimes but it's usually there within the first 20 cards or so)

Actual result

Actual result

Expected result

Issue reproduces how often

Version/Channel Information:

• Can you reproduce this issue with the current Play Store version?
• Can you reproduce this issue with the current Play Store Beta version?
• Can you reproduce this issue with the current Play Store Nightly version?

Device details

• Install type (ARM, x86):
• Device type (Phone, Tablet, Phablet):
• Android version:

Brave version

Website problems only

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

Additional information

[aman-m1]

In Nightly v1.38.6 Android 11 if I toggle off all the sources Brave News never completes loading/circle keeps spinning. And RSS feed from this site doesn't load- https://www.thehindu.com/rssfeeds/

[stephendonner]

In Nightly v1.38.6 Android 11 if I toggle off all the sources Brave News never completes loading/circle keeps spinning. And RSS feed from this site doesn't load- https://www.thehindu.com/rssfeeds/

hi @aman-m1;

1. Known issue: Perpetual spinner on NTP when all sources are disabled  #21158
2. that feed doesn't validate, per the W3C and its doctype: https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fwww.thehindu.com%2Fnews%2Ffeeder%2Fdefault.rss

Please do go ahead and file new issues you see in the latest nightlies; we've love your feedback! Thanks!

[Uni-verse]

Verification completed using Nightly version 1.38.49, Chromium 99.0.4844.74 on Samsung GS 21 running Android 12

Test Plan:

• Add custom RSS source
• Add multiple sources
• Disable custom source from main settings - Tapping on custom RSS feed title deletes feed #21348
• Disable custom source in All Sources
• Disable source from Brave News context menu
• Reload Content Button appears after modifying sources
• Clicking on custom post loads source webpage
• Able to open custom post in New Tab via context menu
• Able to open custom post in Private Tab via context menu
• Custom source shows via Brave news settings bar
• Brave News Settings bar is displayed when scrolling - Brave news settings bar missing when scrolling news after enabling Brave News #21725

Notes:
This issue is still observed - #21272 (comment)
STR : Disable all sources and refresh news feed - #21158

News Settings	Context Menu

[Uni-verse]

Verification completed using Night 1.38.53, Chromium 99.0.4844.74 on Samsung Galaxy Tab S7 running Android 11

Test Plan:

• Add custom RSS source
• Add multiple sources
• Disable custom source from main settings - Tapping on custom RSS feed title deletes feed #21348
• Disable custom source in All Sources
• Disable source from Brave News context menu
• Reload Content Button appears after modifying sources
• Clicking on custom post loads source webpage
• Able to open custom post in New Tab via context menu
• Able to open custom post in Private Tab via context menu
• Custom source shows via Brave news settings bar
• Brave News Settings bar is displayed when scrolling - Brave news settings bar missing when scrolling news after enabling Brave News #21725
• Settings bar is visible when scrolling news feed - Brave News settings bar slightly cut off at the top when scrolling news feed [Android Tablet] #21737

Notes:
This issue is still observed - #21272 (comment)
STR : Disable all sources and refresh news feed - #21158

News Settings	News Feed

[Uni-verse]

@anthonypkeane We may want to triage some of these issues as they are pretty major for this feature in general. I will follow up in the weekly triage/planning meeting.

cc: @SergeyZhukovsky @kjozwiak