HPCC-11820 Add double click support to ECL Playground Graph

Fixes HPCC-11820

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #6164 from GordonSmith/HPCC-11820

HPCC-11820 Add double click support to ECL Playground Graph

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>