[chore][workflow] only run for main repository (#37086)

#### Description

Without this change, when someone makes a PR to `main` in a fork of this
repository, this [workflow
fails](https://github.com/check-spelling-sandbox/opentelemetry-collector-contrib/actions/runs/12663292988)

#### Testing


https://github.com/check-spelling-sandbox/opentelemetry-collector-contrib/actions/runs/12663466736

Signed-off-by: Josh Soref <[email protected]>

Author: jsoref

.github/workflows/check-codeowners.yaml

@@ -24,7 +24,7 @@ jobs:
   setup-environment:
     timeout-minutes: 30
     runs-on: ubuntu-24.04
-    if: ${{ github.actor != 'dependabot[bot]' }}
+    if: ${{ github.actor != 'dependabot[bot]' && github.repository == 'open-telemetry/opentelemetry-collector-contrib' }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
@@ -47,7 +47,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Gen githubgen tool
-        if: github.repository == 'open-telemetry/opentelemetry-collector-contrib'
         run: |
           make githubgen-install
           echo "$(go env GOPATH)/bin" >> $GITHUB_PATH