fix: body length for gzip evaluation

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: alespour

src/main/java/com/influxdb/v3/client/internal/InfluxDBClientImpl.java

@@ -360,7 +360,7 @@ private <T> void writeData(@Nonnull final List<T> data, @Nonnull final WriteOpti
 
         Map<String, String> headers = new HashMap<>(Map.of("Content-Type", "text/plain; charset=utf-8"));
         byte[] body = lineProtocol.getBytes(StandardCharsets.UTF_8);
-        if (lineProtocol.length() >= options.gzipThresholdSafe(config)) {
+        if (body.length >= options.gzipThresholdSafe(config)) {
             try {
                 body = gzipData(body);
                 headers.put("Content-Encoding", "gzip");