[NFC][Clang] Clean up VisitUnaryPlus by removing unused FP feature check (#101412)
This commit removes an unnecessary call to `E->hasStoredFPFeatures()`
within the `VisitUnaryPlus` function. The method's return value was not
being used, leading to a redundant operation. The removal of this line
streamlines the function and eliminates an unneeded check for stored
floating-point features.