chore: update 2.21 system tests hash (#15020)

## Description

<!-- Provide an overview of the change and motivation for the change -->

## Testing

<!-- Describe your testing strategy or note what tests are included -->

## Risks

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## Additional Notes

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Signed-off-by: Juanjo Alvarez <[email protected]>

Author: juanjux

.github/workflows/system-tests.yml

@@ -44,7 +44,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
-          ref: 'e79028841e520eae0604198be4ce10bbad067c63'
+          ref: 'c81c01919ba210b5f8389874a8695f83ba9873de'
 
       - name: Download wheels to binaries directory
         uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
@@ -88,7 +88,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
-          ref: 'e79028841e520eae0604198be4ce10bbad067c63'
+          ref: 'c81c01919ba210b5f8389874a8695f83ba9873de'
 
       - name: Build runner
         uses: ./.github/actions/install_runner
@@ -256,7 +256,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
-          ref: 'e79028841e520eae0604198be4ce10bbad067c63'
+          ref: 'c81c01919ba210b5f8389874a8695f83ba9873de'
       - name: Download wheels to binaries directory
         uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         with: