update for corrected padplane size of TRD-2D

mentioned in merge request computing/cbmroot!565 (merged)

Dear @praisig,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label

assigned to @p.-a.loizeau

For reference: corresponding to macro change in CbmRoot MR 565

merged