feat: added email domain trait to flagsmith (#25928) (#26211)

## Description
> This PR adds the email domain as a default trait in flagsmith. 

#### PR fixes following issue(s)
Fixes #25928 

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#### Type of change
- Chore (housekeeping or task changes that don't impact user perception)

## Testing
>
#### How Has This Been Tested?
> Please describe the tests that you ran to verify your changes. Also
list any relevant details for your test configuration.
> Delete anything that is not relevant
- [x] Manual
- [ ] Jest
- [ ] Cypress
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#### Test Plan
> Add Testsmith test cases links that relate to this PR
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#### Issues raised during DP testing
> Link issues raised during DP testing for better visiblity and tracking
(copy link from comments dropped on this PR)
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## Checklist:
#### Dev activity
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag


#### QA activity:
- [ ] [Speedbreak
features](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#speedbreakers-)
have been covered
- [ ] Test plan covers all impacted features and [areas of
interest](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#areas-of-interest-)
- [ ] Test plan has been peer reviewed by project stakeholders and other
QA members
- [ ] Manually tested functionality on DP
- [ ] We had an implementation alignment call with stakeholders post QA
Round 2
- [ ] Cypress test cases have been added and approved by SDET/manual QA
- [ ] Added `Test Plan Approved` label after Cypress tests were reviewed
- [ ] Added `Test Plan Approved` label after JUnit tests were reviewed

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/CacheableFeatureFlagHelperCEImpl.java

@@ -71,14 +71,19 @@ public class CacheableFeatureFlagHelperCEImpl implements CacheableFeatureFlagHel
         return configService.getInstanceId().map(instanceId -> {
             Map<String, Object> userTraits = new HashMap<>();
             String emailTrait;
+            String emailDomain = userIdentifierService.getEmailDomain(user.getEmail());
             if (!commonConfig.isCloudHosting()) {
                 emailTrait = userIdentifierService.hash(user.getEmail());
+                if (emailDomain != null) {
+                    emailDomain = userIdentifierService.hash(emailDomain);
+                }
             } else {
                 emailTrait = user.getEmail();
             }
             userTraits.put("email", emailTrait);
             userTraits.put("instanceId", instanceId);
             userTraits.put("tenantId", user.getTenantId());
+            userTraits.put("emailDomain", emailDomain);
             userTraits.put("isTelemetryOn", !commonConfig.isTelemetryDisabled());
             // for anonymous user, user.getCreatedAt() is null
             if (user.getCreatedAt() != null) {

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/UserIdentifierServiceCE.java

@@ -7,4 +7,6 @@ public interface UserIdentifierServiceCE {
     String getUserIdentifier(User user);
 
     String hash(String value);
+
+    String getEmailDomain(String email);
 }

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/UserIdentifierServiceCEImpl.java

@@ -34,4 +34,16 @@ public class UserIdentifierServiceCEImpl implements UserIdentifierServiceCE {
     public String hash(String value) {
         return value == null ? "" : DigestUtils.sha256Hex(value);
     }
+
+    @Override
+    public String getEmailDomain(String email) {
+        String emailDomain = null;
+        if (email != null) {
+            int atIndex = email.indexOf('@');
+            if (atIndex > 0) {
+                emailDomain = email.substring(atIndex + 1).toLowerCase();
+            }
+        }
+        return emailDomain;
+    }
 }