CI: Wrap all if: conditions in ${{ }}

While `if:` also works with a bare condition, it is a best practice to always
wrap "dynamic placeholders" in `${{ }}`.

See: https://github.blog/changelog/2026-01-29-github-actions-smarter-editing-clearer-debugging-and-a-new-case-function/#better-if-condition-handling

.github/actions/setup-vtest/action.yml

@@ -34,7 +34,7 @@ runs:
         key: vtest-${{ runner.os }}-${{ runner.arch }}-${{ steps.vtest-sha.outputs.sha }}
 
     - name: Install VTest
-      if: steps.cache-vtest.outputs.cache-hit != 'true'
+      if: ${{ steps.cache-vtest.outputs.cache-hit != 'true' }}
       shell: bash
       run: |
         DESTDIR=${{ github.workspace }}/vtest scripts/build-vtest.sh

.github/workflows/quic-interop-aws-lc.yml

@@ -49,7 +49,7 @@ jobs:
           python run.py -j result.json -l logs-ngtcp2 -r haproxy=local:aws-lc -t "handshake,transfer,longrtt,chacha20,multiplexing,retry,resumption,zerortt,http3,blackhole,keyupdate,ecn,amplificationlimit,handshakeloss,transferloss,handshakecorruption,transfercorruption,ipv6,v2" -c ngtcp2 -s haproxy
 
       - name: Delete succeeded logs
-        if: failure()
+        if: ${{ failure() }}
         run: |
           for client in chrome picoquic quic-go ngtcp2; do
             pushd quic-interop-runner/logs-${client}/haproxy_${client}
@@ -58,7 +58,7 @@ jobs:
           done
 
       - name: Logs upload
-        if: failure()
+        if: ${{ failure() }}
         uses: actions/upload-artifact@v4
         with:
           name: logs

.github/workflows/quic-interop-libressl.yml

@@ -47,7 +47,7 @@ jobs:
           python run.py -j result.json -l logs-quic-go -r haproxy=local:libressl -t "handshake,transfer,longrtt,chacha20,multiplexing,retry,http3,blackhole,amplificationlimit,transferloss,transfercorruption,v2" -c quic-go -s haproxy
 
       - name: Delete succeeded logs
-        if: failure()
+        if: ${{ failure() }}
         run: |
           for client in picoquic quic-go; do
             pushd quic-interop-runner/logs-${client}/haproxy_${client}
@@ -56,7 +56,7 @@ jobs:
           done
 
       - name: Logs upload
-        if: failure()
+        if: ${{ failure() }}
         uses: actions/upload-artifact@v4
         with:
           name: logs