update sampledata users passwords (#11769)

* update sampledata users passwords

* update makefile

Makefile

@@ -290,8 +290,8 @@ test-data: start-docker ## Add test data to the local instance.
 
 	@echo You may need to restart the Mattermost server before using the following
 	@echo ========================================================================
-	@echo Login with a system admin account username=sysadmin password=sysadmin
-	@echo Login with a regular account username=user-1 password=user-1
+	@echo Login with a system admin account username=sysadmin password=Sys@dmin-sample1
+	@echo Login with a regular account username=user-1 password=SampleUs@r-1
 	@echo ========================================================================
 
 validate-go-version: ## Validates the installed version of go against Mattermost's minimum requirement.