Install Python 3.13 to fix failing PR checks with older CLI versions

pr-checks/checks/analyze-ref-input.yml

@@ -2,6 +2,7 @@ name: "Analyze: 'ref' and 'sha' from inputs"
 description: "Checks that specifying 'ref' and 'sha' as inputs works"
 versions: ["default"]
 installGo: true
+installPython: true
 steps:
   - uses: ./../action/init
     with:

pr-checks/checks/local-bundle.yml

@@ -2,6 +2,7 @@ name: "Local CodeQL bundle"
 description: "Tests using a CodeQL bundle from a local file rather than a URL"
 versions: ["linked"]
 installGo: true
+installPython: true
 steps:
   - name: Fetch latest CodeQL bundle
     run: |

pr-checks/checks/multi-language-autodetect.yml

@@ -4,6 +4,7 @@ operatingSystems: ["macos", "ubuntu"]
 env:
   CODEQL_ACTION_RESOLVE_SUPPORTED_LANGUAGES_USING_CLI: true
 installGo: true
+installPython: true
 steps:
   - name: Use Xcode 16
     if: runner.os == 'macOS' && matrix.version != 'nightly-latest'

pr-checks/checks/packaging-codescanning-config-inputs-js.yml

@@ -3,6 +3,7 @@ description: "Checks that specifying packages using a combination of a config fi
 versions: ["linked", "default", "nightly-latest"] # This feature is not compatible with old CLIs
 installGo: true
 installNode: true
+installPython: true
 steps:
   - uses: ./../action/init
     with:

pr-checks/checks/remote-config.yml

@@ -6,6 +6,7 @@ versions:
   - linked
   - nightly-latest
 installGo: true
+installPython: true
 steps:
   - uses: ./../action/init
     with:

pr-checks/checks/unset-environment.yml

@@ -6,6 +6,7 @@ versions:
   - linked
   - nightly-latest
 installGo: true
+installPython: true
 steps:
   - uses: ./../action/init
     id: init

pr-checks/checks/upload-ref-sha-input.yml

@@ -2,6 +2,7 @@ name: "Upload-sarif: 'ref' and 'sha' from inputs"
 description: "Checks that specifying 'ref' and 'sha' as inputs works"
 versions: ["default"]
 installGo: true
+installPython: true
 steps:
   - uses: ./../action/init
     with:

pr-checks/checks/upload-sarif.yml

@@ -3,6 +3,7 @@ description: "Checks that uploading SARIFs to the code quality endpoint works"
 versions: ["default"]
 analysisKinds: ["code-scanning", "code-quality", "code-scanning,code-quality"]
 installGo: true
+installPython: true
 steps:
   - uses: ./../action/init
     with:

pr-checks/checks/with-checkout-path.yml

@@ -2,6 +2,7 @@ name: "Use a custom `checkout_path`"
 description: "Checks that a custom `checkout_path` will find the proper commit_oid"
 versions: ["linked"]
 installGo: true
+installPython: true
 steps:
   # This ensures we don't accidentally use the original checkout for any part of the test.
   - name: Delete original checkout