THRIFT-5562: remove gradle wrapper and use installed gradle 6.9
Client: java
Patch: Jiayu Liu

This closes #2576
diff --git a/debian/rules b/debian/rules
index d0de508..ba886fa 100755
--- a/debian/rules
+++ b/debian/rules
@@ -73,7 +73,7 @@
 
 	# Java
 	cd $(CURDIR)/lib/java && \
-		./gradlew --no-daemon -Prelease=true jar
+		gradle --no-daemon -Prelease=true jar
 
 	# C#
 	$(MAKE) -C $(CURDIR)/lib/netstd