Revert "ci: gate fuzztesting on whether source code changed"

This reverts commit 2203c02347.

.github/workflows/fuzz.yml

@@ -9,20 +9,8 @@ on:
   pull_request:
 
 jobs:
-  Prepare:
-    runs-on: ubuntu-latest
-    outputs:
-      pr_changed_source: ${{ steps.classify_pr.outputs.pr_changed_source }}
-    steps:
-      - name: Checkout Crate
-        uses: actions/checkout@v4
-      - name: Determine what files the PR changes.
-        id: classify_pr
-        run: contrib/classify-pr.sh ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }}
-
   fuzz:
-    needs: Prepare
+    if: ${{ !github.event.act }}
-    if: ${{ !github.event.act }} && needs.Prepare.outputs.pr_changed_source == 'true'
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -76,8 +64,7 @@ jobs:
           path: executed_${{ matrix.fuzz_target }}
 
   verify-execution:
-    needs: Prepare
+    if: ${{ !github.event.act }}
-    if: ${{ !github.event.act }} && needs.Prepare.outputs.pr_changed_source == 'true'
     needs: fuzz
     runs-on: ubuntu-latest
     steps: