Disable scorecard analysis (#2430)

Removes scorecard analysis workflow, as it requires maintenance that the
EngProd team was doing, and it isn't being used in the README anyway.

.github/workflows/scorecards-analysis.yml

@@ -1,55 +0,0 @@
-name: Scorecards supply-chain security
-on:
-  # Only the default branch is supported.
-  branch_protection_rule:
-  push:
-    branches: [ main ]
-
-# Declare default permissions as read only.
-permissions: read-all
-
-jobs:
-  analysis:
-    name: Scorecards analysis
-    runs-on: ubuntu-latest
-    if: ${{ github.repository == 'flutter/samples' }}
-    permissions:
-      # Needed to upload the results to code-scanning dashboard.
-      security-events: write
-      actions: read
-      contents: read
-      id-token: write
-
-    steps:
-      - name: "Checkout code"
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
-        with:
-          persist-credentials: false
-
-      - name: "Run analysis"
-        uses: ossf/scorecard-action@62b2cac7ed8198b15735ed49ab1e5cf35480ba46
-        with:
-          results_file: results.sarif
-          results_format: sarif
-          # Read-only PAT token. To create it,
-          # follow the steps in https://github.com/ossf/scorecard-action#pat-token-creation.
-          repo_token: ${{ secrets.SCORECARD_READ_TOKEN }}
-          # Publish the results to enable scorecard badges. For more details, see
-          # https://github.com/ossf/scorecard-action#publishing-results.
-          # For private repositories, `publish_results` will automatically be set to `false`,
-          # regardless of the value entered here.
-          publish_results: true
-
-      # Upload the results as artifacts (optional).
-      - name: "Upload artifact"
-        uses: actions/upload-artifact@50769540e7f4bd5e21e526ee35c689e35e0d6874
-        with:
-          name: SARIF file
-          path: results.sarif
-          retention-days: 5
-
-      # Upload the results to GitHub's code scanning dashboard.
-      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@4dd16135b69a43b6c8efb853346f8437d92d3c93
-        with:
-          sarif_file: results.sarif