chore: Update text for Rewards user flows (#22881)

Change tracked to enrolled and related strings

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## **Description**

Changing Rewards strings to better terminology "enrolled" / "not
enrolled"

## **Changelog**

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CHANGELOG entry: null

## **Related issues**

Fixes: n/a

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

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### **After**

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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Updates Rewards i18n strings in `locales/languages/en.json` to replace
“opt-in/tracked” with “enrolled” and adjusts related labels/descriptions
and error text.
> 
> - **Rewards i18n (`locales/languages/en.json`)**:
> - Terminology: replace “opt-in/opted in/tracked” with
“enroll/enrolled”.
> - `onboarding.not_supported_account_type_description`: “opted into” →
“enrolled in”.
> - `onboarding.geo_check_fail_description`: “country allows opting
into” → “region allows enrolling into”.
> - `settings.*`: maintain “opted in” counts but update related copy;
error `link_account_failed_error`: “link” → “add”.
> - `link_account_group.tracked/untracked/unsupported/tracked_count`:
“Tracked/Untracked/Unsupported” → “Enrolled/Not enrolled/Not supported”;
count string updated to “enrolled”.
> - Misc: `link_account_failed_error` under settings changed to “Failed
to add account.”
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
d194816. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: Montoya

locales/languages/en.json

@@ -6643,13 +6643,13 @@
       "not_supported_hardware_account_title": "Account not supported",
       "not_supported_hardware_account_description": "Hardware wallet accounts are not eligible to receive rewards yet. Please switch to a different account to proceed.",
       "not_supported_account_type_title": "Account type not supported",
-      "not_supported_account_type_description": "Currently only internal Ethereum and Solana accounts can be opted into the Rewards program. Please switch to a different account to proceed.",
+      "not_supported_account_type_description": "Currently only internal Ethereum and Solana accounts can be enrolled in the Rewards program. Please switch to a different account to proceed.",
       "not_supported_confirm_go_back": "Go back",
       "not_supported_confirm_retry": "Retry",
       "auth_fail_title": "Authentication Failed",
       "auth_fail_description": "Unable to authenticate with the rewards program. Please check your connection and try again.",
       "geo_check_fail_title": "Cannot determine opt-in eligibility",
-      "geo_check_fail_description": "We cannot determine if your country allows opting into the rewards program. Please check your connection and try again.",
+      "geo_check_fail_description": "We cannot determine if your region allows enrolling into the rewards program. Please check your connection and try again.",
       "gtm_title": "Rewards are here",
       "gtm_description": "Earn points for your activity. \nAdvance through levels to unlock rewards.",
       "gtm_confirm": "Get started",
@@ -6696,7 +6696,7 @@
       "link_account_success_title": "{{accountName}} successfully added",
       "link_account_error_title": "Failed to add account",
       "link_account_button": "Add",
-      "link_account_failed_error": "Failed to link account",
+      "link_account_failed_error": "Failed to add account",
       "link_account_unknown_error": "Unknown error occurred"
     },
     "optout": {
@@ -6819,10 +6819,10 @@
     },
     "link_account_group": {
       "link_account": "Add account",
-      "tracked": "Tracked",
-      "untracked": "Untracked",
-      "unsupported": "Unsupported",
-      "tracked_count": "{{optedIn}}/{{total}} tracked",
+      "tracked": "Enrolled",
+      "untracked": "Not enrolled",
+      "unsupported": "Not supported",
+      "tracked_count": "{{optedIn}}/{{total}} enrolled",
       "link_account_success": "{{accountName}} added successfully",
       "link_account_error": "Failed to add one or more addresses for {{accountName}}",
       "link_account_address_error": "Failed to add {{address}}"