fix: re-download cached func CLI binary if not executable

ensureFuncVersion() only checked if the cached binary file existed,
not whether it had execute permission. If the binary lost its execute
bit (e.g. due to a partial download or filesystem issue in CI), the
test would fail with "permission denied" and cascade-fail other specs.

Author: creydr

test/utils/func.go

@@ -187,9 +187,14 @@ func ensureFuncVersion(version string) (string, error) {
 	versionDir := filepath.Join(projectDir, "bin", "func-cli", version)
 	funcBinary := filepath.Join(versionDir, "func")
 
-	// Check if already cached
-	if _, err := os.Stat(funcBinary); err == nil {
-		return funcBinary, nil
+	// Check if already cached and executable
+	if info, err := os.Stat(funcBinary); err == nil {
+		isExecutable := info.Mode().Perm()&0o111 != 0
+		if isExecutable {
+			return funcBinary, nil
+		}
+		// Binary exists but is not executable — remove and re-download
+		os.Remove(funcBinary)
 	}
 
 	// Download the version