[broadcom-dnx]: Install rdb-cli on syncd-dnx (#20948)

This was missed on the original PR and caused show_techsupport sonic-mgmt tests to fail.

Why I did it
PR #19268 replaced redis-rdb-tool with rdb-cli in the Broadcom XGS syncd container. However, it did not do the same for the DNX syncd container, leading to sonic-mgmt failures in show_techsupport tests on DNX platforms.

How I did it
I applied the same change to the Broadcom DNX syncd container.

How to verify it
Run sonic-mgmt show_techsupport tests on a Broadcom DNX DUT.

platform/broadcom/docker-syncd-brcm-dnx.mk

@@ -24,7 +24,7 @@ endif
 
 $(DOCKER_SYNCD_DNX_BASE)_DEPENDS += $(SYNCD)
 $(DOCKER_SYNCD_DNX_BASE)_DEPENDS += $(BRCM_DNX_SAI)
-$(DOCKER_SYNCD_DNX_BASE)_FILES += $(DSSERVE) $(BCMCMD)
+$(DOCKER_SYNCD_DNX_BASE)_FILES += $(DSSERVE) $(BCMCMD) $(RDB-CLI)
 
 ifeq ($(INSTALL_DEBUG_TOOLS), y)
 $(DOCKER_SYNCD_DNX_BASE)_DBG_DEPENDS += $(SYNCD_DBG) \

platform/broadcom/docker-syncd-brcm-dnx/Dockerfile.j2

@@ -23,8 +23,8 @@ RUN apt-get install -yf kmod
 ## BRCM uses ethtool to set host interface speed
 RUN apt-get install -y ethtool
 
-COPY ["files/dsserve", "files/bcmcmd", "start.sh", "start_led.sh", "bcmsh", "/usr/bin/"]
-RUN chmod +x /usr/bin/dsserve /usr/bin/bcmcmd
+COPY ["files/dsserve", "files/bcmcmd", "start.sh", "start_led.sh", "bcmsh", "files/rdb-cli", "/usr/bin/"]
+RUN chmod +x /usr/bin/dsserve /usr/bin/bcmcmd /usr/bin/rdb-cli
 
 COPY ["supervisord.conf", "/etc/supervisor/conf.d/"]
 COPY ["files/supervisor-proc-exit-listener", "/usr/bin"]