Disable Scheduled workflow on forks (#2838)

<!-- Reference any GitHub issues resolved by this PR -->

Closes #

## Introduced changes

<!-- A brief description of the changes -->

-

## Checklist

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- [x] Linked relevant issue
- [x] Updated relevant documentation
- [x] Added relevant tests
- [x] Performed self-review of the code
- [x] Added changes to `CHANGELOG.md`

Author: kkawula

.github/workflows/scheduled.yml

@@ -11,6 +11,7 @@ on:
 
 jobs:
   get-scarb-versions:
+    if: "! github.event.repository.fork"
     name: Get Scarb versions
     outputs:
       versions: ${{ steps.get_versions.outputs.versions }}
@@ -30,6 +31,7 @@ jobs:
           echo "versions=[${scarb_versions[@]}]" >> "$GITHUB_OUTPUT"
 
   test-forge-unit-and-integration:
+    if: "! github.event.repository.fork"
     runs-on: ubuntu-latest
     needs: get-scarb-versions
     strategy:
@@ -50,6 +52,7 @@ jobs:
       - run: cargo test --release -p forge integration
 
   test-forge-e2e:
+    if: "! github.event.repository.fork"
     runs-on: ubuntu-latest
     needs: get-scarb-versions
     strategy:
@@ -89,6 +92,7 @@ jobs:
       - run: cargo test --release -p forge e2e
 
   test-cast:
+    if: "! github.event.repository.fork"
     runs-on: ubuntu-latest
     needs: get-scarb-versions
     strategy: