[Closed] Implement Add/Edit/Delete Segment List Modals

[zackcl]

Closed due to having too many conflicts. I opened another PR: #2353

Changes Include:

• Added addSegmentList endpoint URL (/segments/list) to environment files
• Added addSegmentList, updateSegmentList, and deleteSegmentList functions to segments.data.service.ts for making requests to the backend
• Updated segments actions, effects, and reducer to support adding, updating, and deleting a segment list
• Updated flagId to id in PrivateSegmentListRequest interface for supporting both feature flags and segments
• Added unit tests for segment list operations to SegmentController.test.ts
• Updated flagId to id in FeatureFlagListValidator for consistency with the frontend
• Removed unused functions from feature-flag-exclusions-section-card.component.ts

Endpoints used for adding, updating, and deleting a segment list:

1. On ADD:
   POST /segments/list

2. On EDIT:
   POST /segment

3. On DELETE:
   DELETE /segments/list/:segmentId

[zackcl]

Closing due to having too many conflicts. I opened another PR: #2353