chore(ci): remove pull_request which duplicate pull_request_target

Previously pull_request and pull_request_target events were both
emitted thus leading one cancelling the other because of
concurrency group name format.
Since external contribution needs to be allowed we only need
pull_request_target event.

.github/workflows/aws_tfhe_fast_tests.yml

@@ -11,17 +11,16 @@ env:
   SLACK_ICON: https://pbs.twimg.com/profile_images/1274014582265298945/OjBKP9kn_400x400.png
   SLACK_USERNAME: ${{ secrets.BOT_USERNAME }}
   SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
-  IS_PULL_REQUEST: ${{ github.event_name == 'pull_request' || github.event_name == 'pull_request_target' }}
+  IS_PULL_REQUEST: ${{ github.event_name == 'pull_request_target' }}
 
 on:
   # Allows you to run this workflow manually from the Actions tab as an alternative.
   workflow_dispatch:
-  pull_request:
   pull_request_target:
 
 jobs:
   check-user-permission:
-    if: github.event_name == 'pull_request' || github.event_name == 'pull_request_target'
+    if: github.event_name == 'pull_request_target'
     uses: ./.github/workflows/check_triggering_actor.yml
     secrets:
       TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -135,7 +134,7 @@ jobs:
 
   setup-instance:
     name: Setup instance (fast-tests)
-    if: github.event_name != 'pull_request' ||
+    if: github.event_name != 'pull_request_target' ||
       needs.should-run.outputs.any_file_changed == 'true'
     needs: should-run
     runs-on: ubuntu-latest
@@ -155,8 +154,8 @@ jobs:
 
   fast-tests:
     name: Fast CPU tests
-    if: github.event_name != 'pull_request' ||
-      (github.event_name == 'pull_request' && needs.setup-instance.result != 'skipped')
+    if: github.event_name != 'pull_request_target' ||
+      (github.event_name == 'pull_request_target' && needs.setup-instance.result != 'skipped')
     needs: [ should-run, setup-instance ]
     concurrency:
       group: ${{ github.workflow }}_${{ github.head_ref || github.ref }}