chore: Migrate BOT_GH_TOKEN to SDK_GH_BOT1_TOKEN in workflows (#1392)

Replaces intermediate `BOT_GH_TOKEN` environment variable with direct
`secrets.SDK_GH_BOT1_TOKEN` references in GitHub Actions workflows.

### Changes

- **build-and-test.yml**: Removed unused `BOT_GH_TOKEN` env declaration
- **pr-comment-bot.yml**: Changed `env.BOT_GH_TOKEN` to
`secrets.SDK_GH_BOT1_TOKEN`, removed env declaration

All workflows now reference the secret directly without unnecessary env
variable indirection.

### Checklist

- [x] **All tests pass locally with my changes**
- [x] **I have added tests that prove my fix is effective or that my
feature works**
- [x] **Public components / utils / props are appropriately exported**
- [x] I have added necessary documentation (if appropriate)

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<details>

<summary>Original prompt</summary>

> .github/workflows 에서 BOT_GH_TOKEN 를 SDK_GH_BOT1_TOKEN 로 마이그레이션 하세요


</details>



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---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: bang9 <[email protected]>

Author: Copilot

.github/workflows/build-and-test.yml

@@ -15,9 +15,6 @@ jobs:
   build-and-test:
     runs-on: ubuntu-latest
 
-    env:
-      BOT_GH_TOKEN: ${{ secrets.SDK_GH_BOT1_TOKEN }}
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4

.github/workflows/pr-comment-bot.yml

@@ -7,13 +7,11 @@ jobs:
   pr-comment:
     if : ${{ github.event.issue.pull_request}}
     runs-on: ubuntu-latest
-    env:
-      BOT_GH_TOKEN: ${{ secrets.SDK_GH_BOT1_TOKEN }}
     steps:
       - uses: actions/checkout@v4
       - uses: sendbird/release-automation-action@latest
         with:
-          gh_token: ${{ env.BOT_GH_TOKEN }}
+          gh_token: ${{ secrets.SDK_GH_BOT1_TOKEN }}
           product: 'uikit'
           platform: 'js'
           framework: 'react'