fix(Datagrid): onRowClick results in toggleRow.toggleRowSelected is not a function error in console

[amal-k-joy]

Closes #6547

Added a null check for toggleRowSelected callback since for some rows objects, toggleRowSelected is not present.

How did you test and verify your work?

local

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.78%. Comparing base (cc8f1aa) to head (503ebb0).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6633   +/-   ##
=======================================
  Coverage   80.78%   80.78%           
=======================================
  Files         396      396           
  Lines       12893    12894    +1     
  Branches     4274     4276    +2     
=======================================
+ Hits        10415    10417    +2     
+ Misses       2478     2477    -1     

Components	Coverage Δ
ibm-products	∅ <ø> (∅)
ibm-products-web-components	∅ <ø> (∅)