Remove scorecards and other bading we are no longer tracking/links are borked (flutter/engine#54839)

Similar to the work in https://github.com/flutter/flutter/issues/153626.

engine/src/flutter/.github/workflows/scorecards-analysis.yml

@@ -1,54 +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:
-  scorecards:
-    name: Scorecards analysis
-    runs-on: ubuntu-latest
-    if: ${{ github.repository == 'flutter/engine' }}
-    permissions:
-      # Needed to upload the results to code-scanning dashboard.
-      security-events: write
-      actions: read
-      contents: read
-      # Needed to access OIDC token.
-      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@834a144ee995460fba8ed112a2fc961b36a5ec5a
-        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@2d790406f505036ef40ecba973cc774a50395aac
-        with:
-          sarif_file: results.sarif

engine/src/flutter/README.md

@@ -1,8 +1,6 @@
 # Flutter Engine
 
 [![Flutter CI Status](https://flutter-dashboard.appspot.com/api/public/build-status-badge?repo=engine)](https://flutter-dashboard.appspot.com/#/build?repo=engine)
-[![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/flutter/engine/badge)](https://deps.dev/project/github/flutter%2Fengine)
-[![SLSA 1](https://slsa.dev/images/gh-badge-level1.svg)](https://slsa.dev)
 
 Flutter is Google's SDK for crafting beautiful, fast user experiences for
 mobile, web, and desktop from a single codebase. Flutter works with existing