GH-48142: [CI] Disallow scheduled GitHub Actions run on forked repos (#48143)

### Rationale for this change
Closes #48142
Prevents Github workflows to periodically run on forked repos

### What changes are included in this PR?
Add a gate to the two github workflows to prevent them from periodically running on forked repos. 

### Are these changes tested?
Yes, manually

### Are there any user-facing changes?
No

**This PR includes breaking changes to public APIs.** (If there are any breaking changes to public APIs, please explain which changes are breaking. If not, you can remove this.)

**This PR contains a "Critical Fix".** (If the changes fix either (a) a security vulnerability, (b) a bug that caused incorrect or invalid data to be produced, or (c) a bug that causes a crash (even when the API contract is upheld), please provide explanation. If not, you can remove this.)

* GitHub Issue: #48142

Authored-by: Kevin Liu <[email protected]>
Signed-off-by: Raúl Cumplido <[email protected]>

Author: kevinjqliu

.github/workflows/cpp_extra.yml

@@ -79,6 +79,7 @@ permissions:
 
 jobs:
   check-labels:
+    if: github.event_name != 'schedule' || github.repository == 'apache/arrow'
     uses: ./.github/workflows/check_labels.yml
     secrets: inherit
     with:

.github/workflows/package_linux.yml

@@ -66,6 +66,7 @@ permissions:
 
 jobs:
   check-labels:
+    if: github.event_name != 'schedule' || github.repository == 'apache/arrow'
     uses: ./.github/workflows/check_labels.yml
     secrets: inherit
     with: