fix(core): add faker back as a dependency as it is used (#2201)

## Why is this change needed?

Faker has been removed from the dependencies on the farcaster/core
library by mistake, as it is used in factory.ts .
Re-introducing it will prevent if from being bundled.
Fixes #2031 

## Merge Checklist

_Choose all relevant options below by adding an `x` now or at any time
before submitting for review_

- [x] PR title adheres to the [conventional
commits](https://www.conventionalcommits.org/en/v1.0.0/) standard
- [x] PR has a
[changeset](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#35-adding-changesets)
- [x] PR has been tagged with a change label(s) (i.e. documentation,
feature, bugfix, or chore)
- [x] PR includes
[documentation](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#32-writing-docs)
if necessary.

<!-- start pr-codex -->

---

## PR-Codex overview
This PR re-introduces the `faker` dependency in the `@farcaster/core`
package.

### Detailed summary
- Re-added `@faker-js/faker` dependency in `@farcaster/core`
package.json
- Removed `@faker-js/faker` from devDependencies

> ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your
question}`

<!-- end pr-codex -->

.changeset/honest-students-relax.md

@@ -0,0 +1,5 @@
+---
+"@farcaster/core": minor
+---
+
+re-introducing faker dependency

packages/core/package.json

@@ -24,7 +24,9 @@
     "@noble/hashes": "^1.3.0",
     "bs58": "^5.0.0",
     "neverthrow": "^6.0.0",
+    "@faker-js/faker": "^7.6.0",
     "viem": "^2.17.4"
+
   },
   "scripts": {
     "build": "tsup --config tsup.config.ts",
@@ -38,7 +40,6 @@
   },
   "devDependencies": {
     "@ethersproject/abstract-signer": "^5.7.0",
-    "@faker-js/faker": "^7.6.0",
     "@farcaster/fishery": "2.2.3",
     "@noble/ed25519": "^1.7.3",
     "biome-config-custom": "*",