[Feature Toggle, Autofill.js] Pass through a js feature toggle for autofill

[dbajpeyi]

Task/Issue URL: https://app.asana.com/0/1205996472158114/1208150709359290/f

Description

This PR passes through remote config so that it can be accessed in autofill.js, no other business logic is added on the Android side. It's a simple pass-through.

Remote config was already merged:
duckduckgo/privacy-configuration#2265

Autofill.js PR was already merged with the feature toggle:
duckduckgo/duckduckgo-autofill#619

Steps to test this PR

Fixes bugs like: https://app.asana.com/0/1200930669568058/1206749141089966/f
(With the latest remote config, already merged)

1. Run the android app,
2. Go to https://dplinfo.ssb-ag.de/WebComm/default.aspx?TestingCookie=1
3. Save a password there and reload page,
4. The username should have the key icon, and autofill should work (won't autofill password automatically, that's okay).

Counter test - do the same steps with an older config, with thecanCategorizeUnknownUsername feature disabled. You won't see the key icon.

E.g with https://jsonblob.com/api/1278747279446892544

UI changes

Autofill.js changes only, which were tested already in duckduckgo/duckduckgo-autofill#619

[CDRussell]

discussed this offline.

• i don't think this needs to be in the public API.
• even though it's consistent with the other functions, don't want to add to the public API (have plans to reduce it already)
• alternative: RealAutofillRuntimeConfigProvider can check AutofillFeature directly, and that keeps everything inside of autofill-impl