Communicate speedreader distill result back to tab helper

[kkuehlz]

This can cause pages that pass the URL heuristic to show up as being Speedread.

One known example is cnet.com/news/

[kkuehlz]

Test Plan

(1) Go to sites that work in Speedreader (Guardian, HuffPost, whatever you like). Ensure forward and back navigation between Speedreadable pages and non-Speedreadable pages (for example the news homepage) works as expected.

(2) Ensure that closing and restoring the browser with distilled pages restores with them and distilled, and with the icon present.

(3) cnet.com/news should no longer have the Speedreader icon.

[stephendonner]

Verified PASSED using

Brave	1.31.25 Chromium: 93.0.4577.63 (Official Build) nightly (x86_64)
Revision	ff5c0da2ec0adeaed5550e6c7e98417dac77d98a-refs/branch-heads/4577@{#1135}
OS	macOS Version 11.5.2 (Build 20G95)

(1) Steps:

1. new profile
2. launched Brave
3. enabled Speedreader via brave://settings/appearance
4. confirmed that going back and forth between sfgate.com and https://www.sfgate.com/streaming/article/Netflix-s-Outer-Banks-is-the-well-made-trash-16440428.php?IPID=SFGate-HP-CP-Spotlight and huffpost.com and https://www.huffpost.com/entry/civil-rights-groups-lawsuits-texas-voting-law_n_6137ac0de4b04778c00ac652 showed the default (non-Speedreader) and Speedreader views accordingly.

sfgate.com	sfgate.com article	huffpost.com	huffpost.com article

(2) Steps:

1. new profile
2. launched Brave
3. enabled Speedreader via brave://settings/appearance
4. loaded https://www.huffpost.com/entry/civil-rights-groups-lawsuits-texas-voting-law_n_6137ac0de4b04778c00ac652 and https://www.sfgate.com/streaming/article/Netflix-s-Outer-Banks-is-the-well-made-trash-16440428.php?IPID=SFGate-HP-CP-Spotlight
5. shut down
6. restarted Brave
7. confirmed both of the sites in Setup antimuon repo and use it instead of muon #4 were restored upon relaunch

(3) Steps:

1. new profile
2. launched Brave
3. enabled Speedreader via brave://settings/appearance
4. visited https://www.cnet.com/news/ and confirmed I saw no Speedreader icon