Revert "ci: annotate arm64 pie binary with prerelease mark"

This reverts commit ea19e33494.

That commit (#3521) was a workaround for arm64-pie binaries not being
reproducible: when the Release workflow re-ran on the released event,
arm64-pie produced different bytes than on prereleased, and uploading
under the same filename caused issues. The workaround gave the
prerelease-time variant a `-prerelease` suffix so the two variants
would not overwrite each other.

With the previous commit, build no longer re-runs on released, so
arm64-pie is built exactly once (at prerelease time) and the
reproducibility issue is moot. The workaround is no longer needed
and the file now uses its canonical name."

.github/workflows/release.yml

@@ -119,7 +119,6 @@ jobs:
       GOARM: ${{ matrix.goarm }}
       PIE_ENABLED: ${{ matrix.pie }}
       CGO_ENABLED: 0
-      IS_PRERELEASE: ${{ github.event.release.prerelease }}
 
     steps:
       - name: Checkout codebase
@@ -131,11 +130,6 @@ jobs:
         id: get_filename
         run: |
           export _NAME=$(jq ".[\"$GOOS-$GOARCH$GOARM$PIE_ENABLED\"].friendlyName" -r < release/friendly-filenames.json)
-
-          if [ "$GOARCH" = "arm64" ] && [ "$PIE_ENABLED" = "pie" ] && [ "$IS_PRERELEASE" = "true" ]; then
-            export _NAME="${_NAME}-prerelease"
-          fi
-
           echo "GOOS: $GOOS, GOARCH: $GOARCH, GOARM: $GOARM, RELEASE_NAME: $_NAME"
           echo "ASSET_NAME=$_NAME" >> $GITHUB_OUTPUT
           echo "ASSET_NAME=$_NAME" >> $GITHUB_ENV