[Backend] — Test: `FlagsService.createFlag` allows re-flagging after a flag is resolved

[Olowodarey]

Background

FlagsService.createFlag (src/flags/flags.service.ts) only rejects duplicate
flags when status: FlagStatus.PENDING. Once a flag is resolved or dismissed,
the user should be allowed to raise a new flag. There are no tests confirming
this re-flagging behavior or verifying the duplicate check is limited to pending
status.

Goal

Add tests in src/flags/flags.service.spec.ts (create if absent).

Requirements

1. Pending duplicate: flag exists with status = PENDING → ConflictException.
2. Resolved duplicate allowed: flag exists with status = RESOLVED → new
   flag created successfully.
3. Dismissed duplicate allowed: flag exists with status = DISMISSED → new
   flag created.
4. No existing flag: first flag on market → created.

Acceptance criteria

• Only PENDING duplicate is blocked.
• Post-resolution re-flagging allowed.

[gloskull]

Hello, I have 4 years of experience delivering solutions for projects like this, covering backend, frontend, and smart contract development. After carefully reviewing your requirements, I have a clear understanding of the task and am confident in my ability to deliver a clean, efficient, and thoroughly tested solution on time. I prioritize code quality, maintainability, and industry best practices throughout the development process.
My PR will be submitted in under 10hours.