[FSSDK-12315] Arnica risk fixes (#600)

* [FSSDK-12315] Add persist-credentials: false to all actions/checkout steps

Prevent git credentials from being persisted in .git/config
during GitHub Actions workflows, reducing the risk of
accidental credential exposure through artifacts.

* [FSSDK-12315] Remove unused source_clear_cron workflow

Author: FarhanAnjum-opti

.github/workflows/build.yml

@@ -23,6 +23,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+      with:
+        persist-credentials: false
     - name: set up JDK 8
       uses: actions/setup-java@v2
       with:

.github/workflows/integration_test.yml

@@ -20,6 +20,7 @@ jobs:
         repository: 'optimizely/ci-helper-tools'
         path: 'home/runner/ci-helper-tools'
         ref: 'master'
+        persist-credentials: false
     - name: set SDK Branch if PR
       env: 
         HEAD_REF: ${{ github.head_ref }}

.github/workflows/java.yml

@@ -18,6 +18,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+      with:
+        persist-credentials: false
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
@@ -55,7 +57,9 @@ jobs:
     steps:
       - name: checkout
         uses: actions/checkout@v4
-      
+        with:
+          persist-credentials: false
+
       - name: set up JDK ${{ matrix.jdk }}
         uses: actions/setup-java@v4
         with: