pdl: Follow rename of padding width to size in python parser

Bug: 249491455
Test: atest --host pdl_python_parser_test
(cherry picked from https://android-review.googlesource.com/q/commit:9c8f05b2c8ed77e81e27d0368e59057aa5d6088b)
Merged-In: I0a9176ad9970c45c28fe1f7effee7281868d7a6a
Change-Id: I0a9176ad9970c45c28fe1f7effee7281868d7a6a