HPCC-11788 Remove ECLWatch Tech Preview from legacy ECLWatch

The menu item of the ECLWatch Tech Preview is removed from legacy
ECLWatch.

Signed-off-by: wangkx <kevin.wang@lexisnexis.com>
Merge pull request #6208 from wangkx/h11788a

HPCC-11788 Remove ECLWatch Tech Preview from legacy ECLWatch

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>