Additional "default browser" prompts: variant 2

[LukasPaczos]

Task/Issue URL: https://app.asana.com/0/1208671518894266/1208944504536347/f

Description

Introduces variant 2 of the experiment that proposes new CTAs around setting DDG as a default browser. The PR also adds all of the experiment foundations and abstractions, so the remaining two variants will only be a small formality.

I'm going to follow up on pixels in a separate PR.

Class diagram

Flow diagram

Steps to test this PR

This PR relies on the new A/B/N framework for rollout, so to test you'll need a custom privacy config which includes the feature definition, for example:

"defaultBrowserPrompts": {
  "state": "enabled",
  "exceptions": [],
  "features": {
    "additionalPrompts": {
      "state": "enabled",
      "rollout": {
        "steps": [
          {
            "percent": 100
          }
        ]
      },
      "settings": {
        "activeDaysUntilStage1": 1,
        "activeDaysUntilStage2": 3,
        "activeDaysUntilStop": 5
      },
      "cohorts": [
        {
          "name": "control",
          "weight": 0
        },
        {
          "name": "variant_2",
          "weight": 1
        }
      ]
    }
  },
}

or you can apply this JSON Blob:

diff --git a/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt b/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt
index ca0870311..5a904f76b 100644
--- a/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt
+++ b/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt
@@ -27,4 +27,5 @@ enum class PrivacyFeatureName(val value: String) {
     TrackingParametersFeatureName("trackingParameters"),
 }
 
-const val PRIVACY_REMOTE_CONFIG_URL = "https://staticcdn.duckduckgo.com/trackerblocking/config/v4/android-config.json"
+// const val PRIVACY_REMOTE_CONFIG_URL = "https://staticcdn.duckduckgo.com/trackerblocking/config/v4/android-config.json"
+const val PRIVACY_REMOTE_CONFIG_URL = "https://www.jsonblob.com/api/1329040942036082688"

Once built with the right config, ensure that you don't have DDG app set as a default browser, only then you'll be assigned to the experiment.

Given the example config above:

• after one active day you'll see a dialog pop up
• after additional 2 active days you'll see a highlighted menu icon and a new menu button
• after additional 2 days, the menu button will disappear

If you convert at any point and set DDG app as default browser, the experiment will permanently stop.

Screen_recording_20250115_173728.webm

In the video I'm using the ADB commands to change the date, but any mechanism of date change will be enough :)