Remove experiment cohorts in feedback form code (#6989)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1207908166761516/task/1210979364522298?focus=true

### Description

No longer needed as the experiment is off and just tidying up. Removes
unneeded code from this #6544

### Steps to test this PR

- [ ] Send feedback via the feedback form.
- [ ] Check the pixel contains the atb parameter
- [ ] The pixel should only contain the atb without any cohorts

### UI changes
N/A

Author: mikescamell

app/src/main/java/com/duckduckgo/app/di/NetworkModule.kt

@@ -22,7 +22,6 @@ import com.duckduckgo.app.feedback.api.FeedbackSubmitter
 import com.duckduckgo.app.feedback.api.FireAndForgetFeedbackSubmitter
 import com.duckduckgo.app.feedback.api.SubReasonApiMapper
 import com.duckduckgo.app.global.api.*
-import com.duckduckgo.app.onboardingdesignexperiment.OnboardingDesignExperimentManager
 import com.duckduckgo.app.statistics.pixels.Pixel
 import com.duckduckgo.app.statistics.store.StatisticsDataStore
 import com.duckduckgo.appbuildconfig.api.AppBuildConfig
@@ -173,7 +172,6 @@ class NetworkModule {
         @AppCoroutineScope appCoroutineScope: CoroutineScope,
         appBuildConfig: AppBuildConfig,
         dispatcherProvider: DispatcherProvider,
-        onboardingDesignExperimentManager: OnboardingDesignExperimentManager,
     ): FeedbackSubmitter =
         FireAndForgetFeedbackSubmitter(
             feedbackService,
@@ -184,7 +182,6 @@ class NetworkModule {
             appCoroutineScope,
             appBuildConfig,
             dispatcherProvider,
-            onboardingDesignExperimentManager,
         )
 
     companion object {

app/src/main/java/com/duckduckgo/app/feedback/api/FeedbackSubmitter.kt

@@ -25,7 +25,6 @@ import com.duckduckgo.app.feedback.ui.negative.FeedbackType.MainReason.OTHER
 import com.duckduckgo.app.feedback.ui.negative.FeedbackType.MainReason.SEARCH_NOT_GOOD_ENOUGH
 import com.duckduckgo.app.feedback.ui.negative.FeedbackType.MainReason.WEBSITES_NOT_LOADING
 import com.duckduckgo.app.feedback.ui.negative.FeedbackType.SubReason
-import com.duckduckgo.app.onboardingdesignexperiment.OnboardingDesignExperimentManager
 import com.duckduckgo.app.pixels.AppPixelName
 import com.duckduckgo.app.pixels.AppPixelName.FEEDBACK_NEGATIVE_SUBMISSION
 import com.duckduckgo.app.statistics.pixels.Pixel
@@ -66,7 +65,6 @@ class FireAndForgetFeedbackSubmitter(
     private val appCoroutineScope: CoroutineScope,
     private val appBuildConfig: AppBuildConfig,
     private val dispatcherProvider: DispatcherProvider,
-    private val onboardingDesignExperimentManager: OnboardingDesignExperimentManager,
 ) : FeedbackSubmitter {
     override suspend fun sendNegativeFeedback(
         mainReason: MainReason,
@@ -150,13 +148,6 @@ class FireAndForgetFeedbackSubmitter(
         url: String? = null,
         reason: String = FeedbackService.REASON_GENERAL,
     ) {
-        // Delete after the experiment has finished and go back to always return atbWithVariant()
-        val atb = if (onboardingDesignExperimentManager.isAnyExperimentEnrolledAndEnabled()) {
-            atbWithVariant() + "_${onboardingDesignExperimentManager.getCohort()}"
-        } else {
-            atbWithVariant()
-        }
-
         feedbackService.submitFeedback(
             reason = reason,
             category = category,
@@ -168,7 +159,7 @@ class FireAndForgetFeedbackSubmitter(
             manufacturer = Build.MANUFACTURER,
             model = Build.MODEL,
             api = appBuildConfig.sdkInt,
-            atb = atb,
+            atb = atbWithVariant(),
         )
     }