Revert CSV related changes to import docs

!176760 was already
merged, but describes behaviour not likely to be fully released until
17.10. To avoid confusing users, we should omit it from the docs
until the next milestone.

app/assets/javascripts/members/placeholders/components/csv_upload_modal.vue

@@ -87,7 +87,7 @@ export default {
   },
   dropzoneAllowList: ['.csv'],
   docsLink: helpPagePath('user/project/import/_index', {
-    anchor: 'request-reassignment-by-using-a-csv-file',
+    anchor: 'reassign-contributions-and-memberships',
   }),
   i18n: {
     description: s__(

doc/user/project/import/_index.md

@@ -236,13 +236,10 @@ Users with the Owner role for a top-level group can reassign contributions and m
 from placeholder users to existing active (non-bot) users.
 On the destination instance, users with the Owner role for a top-level group can:
 
-- Request users to review reassignment of contributions and memberships [in the UI](#request-reassignment-in-ui)
-  or [through a CSV file](#request-reassignment-by-using-a-csv-file).
-  For a large number of placeholder users, you should use a CSV file.
-  In both cases, users receive a request by email to accept or reject the reassignment.
-  The reassignment starts only after the selected user
-  [accepts the reassignment request](#accept-contribution-reassignment).
-- Choose not to reassign contributions and memberships and [keep them assigned to placeholder users](#keep-as-placeholder).
+- Request users to accept reassignment of contributions and membership [in the UI](#request-reassignment-in-ui).
+  The reassignment process starts only after the selected user [accepts the reassignment request](#accept-contribution-reassignment),
+  which is sent to them by email.
+- Choose not to reassign contributions and memberships, and [keep them with placeholder users](#keep-as-placeholder).
 
 All the contributions initially assigned to a single placeholder user can only be reassigned to a single active regular
 user on the destination instance. The contributions assigned to a single placeholder user cannot be split among multiple
@@ -318,50 +315,6 @@ Contributions of only one placeholder user can be reassigned to an active non-bo
 
 Before a user accepts the reassignment, you can [cancel the request](#cancel-reassignment-request).
 
-#### Request reassignment by using a CSV file
-
-> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/455901) in GitLab 17.9 [with a flag](../../../administration/feature_flags.md) named `importer_user_mapping_reassignment_csv`. Disabled by default.
-
-FLAG:
-The availability of this feature is controlled by a feature flag.
-For more information, see the history.
-This feature is available for testing, but not ready for production use.
-
-Prerequisites:
-
-- You must have the Owner role for the group.
-
-For a large number of placeholder users, you might want to
-reassign contributions and memberships by using a CSV file.
-If placeholder users are awaiting reassignment, you can download
-a prefilled CSV template with the following information.
-For example:
-
-| Source host          | Import type | Source user identifier | Source user name | Source username |
-|----------------------|-------------|------------------------|------------------|-----------------|
-| `gitlab.example.com` | `gitlab`    | `alice`                | `Alice Coder`    | `a.coer`        |
-
-Do not update **Source host**, **Import type**, or **Source user identifier**.
-This information locates the corresponding database record
-after you've uploaded the completed CSV file.
-**Source user name** and **Source username** identify the source user
-and are not used after you've uploaded the CSV file.
-
-To request reassignment of contributions and memberships by using a CSV file:
-
-1. On the left sidebar, select **Search or go to** and find your group.
-1. Select **Manage > Members**.
-1. Select the **Placeholders** tab.
-1. Select **Reassign with CSV**.
-1. Download the prefilled CSV template.
-1. In **GitLab username** or **GitLab public email**, enter the username or email address
-   of the GitLab user on the destination instance.
-   You can use only public email addresses for reassignment.
-1. Upload the completed CSV file.
-1. Select **Reassign**.
-
-Users receive an email to review and accept any contributions reassigned to them.
-
 #### Keep as placeholder
 
 You might not want to reassign contributions and memberships to users on the destination instance. For example, you