Remove native implementation of the site brekage reporting screen (#5483)

Task/Issue URL:
https://app.asana.com/0/488551667048375/1208540813186997/f

### Description

This PR removes native implementation of the site breakage reporting
screen, which is currently hidden by a feature flag. We migrated to the
web version of that form for several months and don't intend to go back
to using native one.

### Steps to test this PR

#### Navigate to the screen through Privacy Dashboard
- [x] Navigate to any website
- [x] Tap shield icon in the toolbar
- [x] Tap "Website not working?"
- [x] Verify that you landed on site breakage report screen and can send
the report

#### Navigate to the screen through the options menu
- [x] Navigate to any website
- [x] Tap "Report Broken Site" in the options menu
- [x] Verify that you landed on site breakage report screen and can send
the report

#### Navigate to the screen through the CTA shown on refreshing
- [x] Navigate to any website
- [x] Refresh 3 times in <20s
- [x] Tap "Report Broken Site" on the CTA that appears
- [x] Verify that you landed on site breakage report screen and can send
the report

### No UI changes

Author: lmac012

app/src/main/AndroidManifest.xml

@@ -348,12 +348,6 @@
             android:exported="false"
             android:label="@string/feedbackActivityTitle"
             android:windowSoftInputMode="adjustResize" />
-        <activity
-            android:name="com.duckduckgo.app.brokensite.BrokenSiteActivity"
-            android:exported="false"
-            android:label="@string/brokenSiteHeading"
-            android:windowSoftInputMode="adjustResize"
-            android:parentActivityName=".BrowserActivity" />
         <activity
             android:name="com.duckduckgo.app.survey.ui.SurveyActivity"
             android:configChanges="keyboardHidden|orientation|screenSize|smallestScreenSize|screenLayout|navigation|keyboard"